Uğur Serencam

Summary: Generally, wind energy production is based on the average wind speed without any classification. This article proposes a classification system on the basis of wind speed durations greater than a given threshold value. For this purpose, the wind quality designation (WQD) concept is defined based on the wind potential duration, amount, and intensity on a threshold level. Its classifications are depicted on five risk percentage classes as “excellent,” “very good,” “good,” “fair,” and “weak. Apart from the classification, the change of WQD with wind speed threshold provides qualitative and quantitative wind speed energy production assessment. The specific objective of the article is to present theoretical WQD explanations on the basis of the most frequently employed two‐parameter Weibull probability distribution function (PDF). The application is provided for Adiyaman City, Kahta meteorology station wind speed records from the Southeastern province of Turkey. It is noticed that there is no “Weak” category at this station and the most effective quality class is “Excellent” from 14 m/s to almost 27 m/s wind speeds. The average wind speed corresponds to about 62% WQD. Finally, the wind speed potential durations PDF abides by the logarithmic‐normal PDF, whereas amount and intensity accord with the Weibull PDFs.

Geometric parameters in solar chimney power plants are numerically optimised for the purpose of better power output figures. Several parameters have been investigated in the pilot plant such as chimney height and diameter, collector diameter and slope, and slenderness. However, ground slope has not been studied to date despite its perspicuous impact on turbulent flow. In this study, the impacts of the different slope angles of the ground, where the solar radiation is absorbed through the collector, on the main performance parameters of the system are numerically analysed through a reliable CFD software ANSYS FLUENT. By considering the actual geometric figures of the pilot plant, a 3D model is constructed through DO (discrete ordinates) solar ray tracing algorithm and RNG k-ε turbulence model. For the solar intensity of 1000W/m², the maximum velocity inside the system is found to be 14.2m/s, which is in good accordance with the experimental data of 15.0m/s. Starting from 5m inside the collector, the chimney inlet heights are reconfigured 0.209, 0.419, 0.625, 0.838, and 1.04m, respectively, and when the ground slope is 0.1, 0.2, 0.3, 0.4, and 0.5, the changes in the performance output of the system are investigated. For the reference case which refers to the horizontal ground, the maximum air velocity is determined to be 14.2m/s and the power output is 54.3kW. However, when the ground slope is made 0.5, it is observed that the maximum velocity increases by 37 to 19.51m/s, and the power output is enhanced to 63.95kW with a rise of 17.7. Sloping ground is found a key solution to improve the turbulent effects inside the plant, thus to enhance the electrical power output.

Turkey has many problems due to its increasing energy consumption and rapid economic growth. Foreign energy dependency adversely affects sustainable development of the country by hindering its economic development. Turkey has a yearly total 433 TWh hydropower capacity and 151 TWh yearly economical capacity. The electricity demand of Turkey will reach to around 420 TWh annually by 2020. Turkey had 521 operational hydropower plants with a total capacity of almost 24,000 MW in 2014. This corresponds to 34% of the total capacity. Within the first 8 months of 2015, 8 more hydropower plants came online with a capacity of around 1,240 MW. The share of hydro in power generation capacity went up by 1% during the first five months of the year reaching 35% from its previous 34% level in 2014.