Low Cut-in Speed Research Articles

IDENTIFICATION OF POTENTIAL SITES FOR HARVESTING TIDAL CURRENT POWER IN KELIAN CAPE, KELABAT BAY, AND LARANTUKA STRAIT

Harvesting of power from tidal currents is part of an emerging effort to capture energy fromrenewable sources, as non-renewable energy resources are depleted. The Indonesian government plans todevelop tidal energy power generators in several areas and is conducting assessments in Bangka Belitungprovince at two locations in Kelian Cape and Kelabat Bay and in the province of East Nusa Tenggara atLarantuka Strait. Three potential locations namely Kelian Cape, Kelabat Bay, and Larantuka Strait, is assessed.Field measurements, numerical modeling, and potential site analysis are carried out. Both tidal elevation andtidal current validation between field measurement data and numerical modeling results are carried out andshow good agreement. MIKE 3 (licensed) is used for the modeling process The Kelian Cape model presentsthree potential sites at Kelian Cape, with a peak velocity of 1.4 m/s. The Kelabat Bay model gives five potentialsites, located at the bay’s narrowest point, with a peak velocity of 1.15 m/s. The Larantuka Strait model givesfour potential sites in the narrowest area, with a peak velocity of 2.5 m/s. Larantuka Strait is found to have themost potential for the harvesting of tidal current power, as the current velocity at Larantuka Strait is higher,meaning that turbine devices with higher cut-in speeds are suitable. In Kelian Cape and Kelabat Bay, deviceswith low cut-in speed such as the Gorlov Helical Turbine or Sabella Turbine are required.

Prediction of the Mechanical Power in Wind Turbine Powered Car UsingVelocity Analysis

Savonius is a drag type vertical axis wind turbine. Savonius wind turbines have a low cut-in speed and can operate at low wind speed. It is suitable for small scale power generation, such as individual domestic installations. In this paper, investigation into the relationship between the type of Savonius rotor, the torque and the mechanical power generated was carried out. Also an illustration on how the type of rotor plays an important role in the prediction of mechanical power of wind turbine powered car. The main purpose of this paper is to predict and investigate the aerodynamic effects by means of velocity analysis on the performance of a wind turbine powered car by converting the wind energy to mechanical energy to overcome load applied on the rotating main shaft. The predicted result based on theoretical analysis is compared with experimental results obtained from literature. Prediction of the torque was done at a wind speed of 4 m/s, and an angular velocity of 130 RPM according to meteorological statistics in Northern Cyprus.

Assessment of C-Type Darrieus Wind Turbine Under Low Wind Speed Condition

Harvesting wind energy in in a low wind speed region is deem un-economical if not daunting task. Study shows that a minimum cut in speed of 3.5 m/s is required to extract a meaningful wind energy for electricity while a mean speed of 6 m/s is preferred. However, in Malaysia the mean speed is at 2 m/s with certain potential areas having 3 m/s mean speed. Thus, this work aims to develop a wind turbine that able to operate at lower cut-in speed and produce meaningful power for electricity generation. A C-type Darrieus blade is selected as it shows good potential to operate in arbitrary wind speed condition. The wind turbine is designed and fabricated in UMS labs while the performance of the wind turbine is evaluated in a simulated wind condition. Test result shows that the wind turbine started to rotate at 1 m/s compared to a NACA 0012 Darrieus turbine that started to rotate at 3 m/s. The performance of the turbine shows that it have good potential to be used in an intermittent arbitrary wind speed condition as well as low mean wind speed condition.

Wind energy potential assessment of Cameroon's coastal regions for the installation of an onshore wind farm.

For the future installation of a wind farm in Cameroon, the wind energy potentials of three of Cameroon’s coastal cities (Kribi, Douala and Limbe) are assessed using NASA average monthly wind data for 31 years (1983–2013) and compared through Weibull statistics. The Weibull parameters are estimated by the method of maximum likelihood, the mean power densities, the maximum energy carrying wind speeds and the most probable wind speeds are also calculated and compared over these three cities. Finally, the cumulative wind speed distributions over the wet and dry seasons are also analyzed. The results show that the shape and scale parameters for Kribi, Douala and Limbe are 2.9 and 2.8, 3.9 and 1.8 and 3.08 and 2.58, respectively. The mean power densities through Weibull analysis for Kribi, Douala and Limbe are 33.7 W/m2, 8.0 W/m2 and 25.42 W/m2, respectively. Kribi’s most probable wind speed and maximum energy carrying wind speed was found to be 2.42 m/s and 3.35 m/s, 2.27 m/s and 3.03 m/s for Limbe and 1.67 m/s and 2.0 m/s for Douala, respectively. Analysis of the wind speed and hence power distribution over the wet and dry seasons shows that in the wet season, August is the windiest month for Douala and Limbe while September is the windiest month for Kribi while in the dry season, March is the windiest month for Douala and Limbe while February is the windiest month for Kribi. In terms of mean power density, most probable wind speed and wind speed carrying maximum energy, Kribi shows to be the best site for the installation of a wind farm. Generally, the wind speeds at all three locations seem quite low, average wind speeds of all the three studied locations fall below 4.0m/s which is far below the cut-in wind speed of many modern wind turbines. However we recommend the use of low cut-in speed wind turbines like the Savonius for stand alone low energy needs

Airfoil Selection Methodology for Small Wind Turbines

On wind turbine technology, the aerodynamic performance is fundamental to increase efficiency. Nowadays there are several databases with airfoils designed and simulated for different applications, that is why it is necessary to select those suitable for a specific application. This work presents a new methodology for airfoil selection used in feasibility and optimization of small wind turbines with low cut-in speed. On the first stage airfoils data is tested on XFOIL software to check its compatibility with the simulator; then, arithmetic mean criteria is recursively used to discard underperformed airfoils; the best airfoil data was exported to Matlab for a deeper analysis. In the second part, data points were interpolated using “splines” to calculate glide ratio and stability across multiple angles of attack, those who present a bigger steadiness were conserved. As a result, 3 airfoils, from an initial group of 189, were selected due to its performance above the average as exemplification of the methodology.

Assessment of solar and wind power resources in Osogbo (SW Nigeria - 7°47"N, 4°29"E) for viability of hybrid power applications

The solar-radiation over Osogbo (7°47N, 4°29E) was estimated from sunshine-hours to determine the available solar energy for deployment of solar photovoltaic technology applications. The computed mean-monthly daily solar-radiation ranges from 10.30 MJm−2day−1 (August) to 18.10 MJm−2day−1 (February). Analysis of daily wind speeds shows an annual-mean wind speed of 3.5 m/s at 18 m height with peak values of about 4.9 m/s occurring correspondingly at the peak of the rainy season. This study shows that wind power can compliment photovoltaic applications. Batteries can be used to overcome the well-known variability of wind power. In a pilot scheme, a wind turbine with low cut-in speed of 3 m/s was installed at 18 m height to compliment a 400 Wp solar module and a 4.8 KW-hrs battery-bank/inverter system, to form a robust hybrid alternative power system. The study establishes that wind resources of wind-power class-2 and above can compliment small-scale photovoltaic systems to overcome lower performance challenges during periods of heavy cloud-cover.

Rayleigh Distribution-Based Model for Prediction of Wind Energy Potential of Cameroon

Modelling and prediction of wind characteristics are essential design inputs in the development of wind energy systems. This paper exploits the characteristics of the Rayleigh probability density function to analyse the wind potential of all the regions of the republic of Cameroon. In the procedure, the probability density (PD) curves of some representative towns of the ten regions of Cameroon are presented. These curves highlight the fraction of time for which some wind velocity V prevails at the sites and the most frequent wind speed expected at these sites which coincide with the peak of the PD curves. We then proceed to calculate the power density of the sites, as well as the energy available for wind turbine extraction. We recommend the Savonius rotor for the regions of low wind speed based on its low cut-in speed of 1m/s.