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The paper presents an in-depth analysis regarding the market potential of unconventional wind turbines from a technological perspective. The envisaged solutions were identified in literature and are currently in different development stages. The aim of the analysis is to estimate which types of wind turbines are suitable for further development and have the potential to replace someday the traditional vertical axis wind turbines with three blades that currently represent the best solution for onshore and offshore wind farms. The development of wind power conversion solutions is a current topic due to low carbon energy policies and presents several challenges. Essentially, it needs to be cost competitive compared with fossil fuels technologies and other renewable energy sources, especially photovoltaic (PV) power plants that recently gained ground due to a continuous reduction of manufacturing costs. Both the PV and wind turbines must have a complementary approach for a good energy mix. The technology of the wind turbines of today is continuously improved in order to increase their competitiveness on the market. Further developments are expected both for large capacity wind turbines and for low power concepts while the reliability over time will determine the best solution that will be adopted and maintained for years to come. Not all the solutions can have future development potential, but some results and approaches can be applied in the industry having a positive impact in terms of production cost and energy conversion efficiency. [ABSTRACT FROM AUTHOR]

Hydro-kinetic turbines operate by using the kinetic energy of the water current in order to produce electric power. The kinetic energy is easily accessible on most rivers, triggering an increasing interest for such devices. Unfortunately, the low power density represents an important barrier to large-scale commercialization. Theoretical Betz law limits the extracted power coefficient to 0.59, but the real on site maximum values range from 0.4 to 0.45. However, a shroud placed around the rotor increases the power output by concentrating the flow from a larger surface and locally increasing the velocity. Thus, the design of the rotor blades is a very complex process due to the fact that the performance of these turbines depends on various parameters like number of blades, tip speed ratio, air foil type, blade pitch, chord length and twist angle along the blade. The paper aims to maximize the performance of a horizontal axis hydrokinetic turbine by assessing the blade chord length influence on the efficiency of such a turbine. The blade chord length and twist angle are firstly calculated, and then validated using Qblade software application. The computations and simulations are performed for a rotor provided with available data from previous tests achieved on site. [ABSTRACT FROM AUTHOR]

The primary objective of this paper is to study the influence of orifices diameter on an ecological water intake by using experimental modelling techniques. The tests have been performed on a small scale model integrated in a dedicated test stand. Experimental modelling of the water intake has enabled the characterization of specific hydraulic parameters, as well as estimations of intake capacity. A small scale model was developed starting from a simplified version of a sand-less ecological intake. Thus, it was possible to determine the mean water velocities from the main channel and the captured flow when testing perforated surfaces with different orifice diameters. The conclusions resulting from experiments are relevant for establishing the main design criteria of such intakes, their limitations and the factors determining their optimal operation. The carried out tests have been aimed at studying the behaviour of an environmental friendly intake in certain operation conditions. The scale model was designed to meet a certain flexibility, which enables testing with variable slope angle, embankment position and different orifice size. The obtained values related to the experimental model can be extrapolated to the prototype by using Froude similarity condition. Therefore, the results for the experimental model can be extended and used for other water works with similar site-specific design data. [ABSTRACT FROM AUTHOR]

This paper presents the assessment of wind energy probability by using the Weibull distribution function for Topraisar area, Constanta County, Romania. Putting into service of a counter rotating wind turbine within an area with superior energy potential is to be foreseen. Following the analysis of several initial locations, Topraisar area in Constanta County, was selected as the optimum location for setting-up the meteorological parameters monitoring system, specifically for the wind turbine to be referred at. Monitoring of the meteorological parameters is required for controlling the available energy and, subsequently, for sizing and designing of the wind turbine, in scope of maximizing the extracted energy. [ABSTRACT FROM AUTHOR]

The paper presents solutions for improving the efficiency of the wind energy conversion into electricity by using counter rotating wind turbine systems and permanent magnets electric generators. The innovative design of the generators allows obtaining an increased speed and eliminates the speed multiplier. This design leads to an improved efficiency on the entire energy conversion system. The electric machine has both rotating armatures, each of them being entrained by a wind rotor. One rotor rotates clockwise, while the other counterclockwise. There are presented the results obtained for testing a generator with mobile armatures used for undertaking the movement provided by a counter rotating horizontal axis wind turbine (CRHAWT) system and elements of designing a model of counter rotating vertical axis wind turbine (CRVAWT) system. [ABSTRACT FROM AUTHOR]

During the experimental test of a propulsion boat supplied from renewable energies (solar and hydraulic), we achieved some relevant result about the mains characteristics of it. The test was performed on Danube, near the Tulcea City. The preliminary results of the tests underlined the opportunity and importance of developing a sustainable tourist river transport, based on electric propulsion systems, in Danube Delta Biosphere Area. Also is important to taking in to account the possibility to supply the energy needed for this propulsion system of the boats (with CO2 zero emission level), by the several renewable energy resources, existing in this area (solar-energy, hydro-energy, wind energy). [ABSTRACT FROM AUTHOR]

This paper presents both the wave channel that has been designed and achieved within a research program and the sets and parts of the model that have been experimented and put into practice. An experimental model has been devised and it is made up of a frame in which a Perspex tub is positioned, a cylinder suspended by two arms, a crank powered by a worm gear motor. The latter is fed by a three phase voltage motor controller. [ABSTRACT FROM AUTHOR]

The following paper presents numeric results for the dynamic stress of the structure of the hydrodynamic station, considering the wave power against it, focusing on the response of the base section of the station. The numeric results were received through iterative calculi made by a finite element soft. The goal of the project is to study the response of important parts of the wave driven hydro pneumatic station, and particularly, the response of the base section of it. [ABSTRACT FROM AUTHOR]