The wind power potential of the eastern Mediterranean region of Turkey

The wind energy potential in the eastern Mediterranean region has been investigated using hourly wind data taken from seven stations during 1992-2001 periods by the Turkish Meteorological Service. The present work suggests that in the east Mediterranean Sea coast of Turkey, wind energy sources are convenient for electricity generation. The mean power density was determined as 500 W/m² in many areas of this region at 25 m from the ground level. The most promising locations in terms of wind power generation are identified. The contours of constant wind speed and power potential could lead the private power developers to decide the locations of appropriate wind farms.     

Erratum

Erratum: Wind and tall buildings: Negatives and positives The above‐mentioned article was published online on 3 November 2008 (DOI: 10.1002/tal.482). Some errors were subsequently identified within section 3·1 Wind turbines. Please find the corrected version below: […] The available power per square metre of approaching wind may be calculated from (3) where ρ is the air density (about 1·2 kg/m³), is the average of the cube of wind speed. Assuming the wind speed distribution is approximately Rayleigh in form, then may be estimated using . Therefore, the available power in the wind at turbine height is calculated to be (4) To calculate the energy extracted by the turbine, the available wind power P is multiplied by the turbine area and the turbine efficiency. Even an ideal turbine cannot exceed about 59% efficiency (the so‐called Betz limit) because much of the airflow tends to deflect around the turbine due to the turbine drag. Real turbines typically do not achieve overall efficiencies above about 40%. Assuming 40% efficiency, the 52‐m diameter turbine will therefore extract the following energy E from the wind (5) where 8766 is the number of hours per year. Assuming the building uses approximately 300 kWh/(year·m²) and that the used floor area is about 45000 m², its energy consumption will be 13·5 GWh/year. […]     

Bestimmung thermischer Eigenschaften der Gesteine des Unteren und Mittleren Buntsandsteins

For accurate planning of vertical borehole heat exchanger systems, knowledge of thermo-physical ground parameters is critical. This study reports laboratory-measured thermal conductivity and diffusivity values of Mesozoic sandstones (Lower and Middle Buntsandstein) from four wells. The measurements were made on drill core using an optical scanning method. The mean thermal conductivities of the sandstones range between 2.6?±?0.3 W?/?(m?·?K) and 3.1?±?0.4 W?/?(m?·?K) for dry conditions and between 3.6?±?0.3 W?/?(m?·?K) and 4.1?±?0.6 W?/?(m?·?K) after saturation with water. The mean thermal diffusivity values range between (1.6?±?0.2)?·?10??6 m²?/?s for dry and (2.0?±?0.6)?·?10??6 m²?/?s for water-saturated sandstones. Thermal properties are closely related to the petrography and lithostratigraphy of the sandstones. Additionally, three temperature correction methods were applied for the purpose of evaluating the comparative accuracy and the correction schemes with respect to local in-situ conditions. The results show that the temperature corrections proposed by Somerton (Thermal properties on temperature-related behavior of rock/fluid systems, Elsevier, New York, S 257, 1992) and Sass et al. (J Geophys Res, 97:5017–5030, 1992) are most suited for the respective sandstone data set.     

A preliminary study of wind–solar hybrid systems potential in Jammu and Kashmir

ABSTRACT

This paper deals with the study of wind–solar hybrid systems in the region of Jammu and Kashmir. Due to scarcity of less renewable energy resources in the J&K region, National Institute of Wind Energy, Chennai had installed different wind monitoring stations to measure the wind data at different locations. The survey reveals that four districts (LEH, KARGIL, POONCH and REASI) are suitable for small wind–solar hybrid systems. BIDDA (REASI) and CHUSHUL (LEH) are the two sites for small wind farm development due to the highest wind speed (more than 7?m/s) and power density (more than 400?W/m²) at 100?m agl.     

Improved design of tubular wind tower foundations using steel micropiles

The constant increase in the wind power production leads to the need of higher wind towers, which brings up some questions regarding the effectiveness of tubular towers and respective foundations. This work focuses on the comparative structural design, life cycle behaviour and costs of onshore concrete shallow foundations for tubular wind towers (WT) when steel micropiles are used to improve resistance of the soil–structure interface (hybrid foundation). Typical wind loading for Turbine Class II and moderate seismicity (.25 g peak ground acceleration) is used to design and analyse 18 WT foundation case studies. This allows the comparison between shallow and hybrid foundations designed for three different hub heights and respective turbine rated power (80 m/2 MW, 100 m/3.6 MW and 150 m/5 MW) and for three different tubular tower solutions (steel, concrete and hybrid steel–concrete). The possible benefits of the solution using steel grouted micropiles are discussed in terms of potential environmental and economic impacts using life cycle analysis. The use of micropiles reveals to be an interesting solution to improve common shallow WT foundations since it allows the reduction of the dimensions of the foundation leading to significant environmental and cost benefits.     

Computational Analysis of Fire Dynamics Inside a Wind Turbine

Wind turbines are generally considered cost-effective, reliable and sustainable energy sources. Fires are not common in wind turbines, but a significant number of fires occur every year due to the large number of turbines installed. Wind turbine fires are difficult to extinguish hence significant damage is expected. Due to the unmanned operation, the probability of a turbine being occupied during a fire is very low. However, operators can do several tasks every week, and hence be exposed to a certain risk. Moreover, there is a general lack of information about how a fire develops inside a wind turbine and the subsequent evolution of the tenability conditions during the time required for an eventual evacuation. Gamesa has been working on fire safety since 2013, using CFD fire modelling to provide insights on wind turbine fire development for the design of emergency procedures. The paper describes a fire hazard analysis performed in a Gamesa’s 2.5 MW turbine. A CFD simulation is carried out to estimate the effects during the first minutes of a typical wind turbine fire in an electrical cabinet. Results show that average oxygen concentration at the nacelle remains above 19.5% during the first 10 min; temperature remains below 60°C for 12 min if measured at 1.5 m; and visibility is on average assured at heights lower than 1.5 m, with values above 5 m during the first 8 min in worse locations, implying no danger for personnel. The potential of this type of analysis to design safer wind turbines under performance-based approaches is clearly demonstrated.     

Energy output estimation for small-scale wind power generators using Weibull-representative wind data

Estimation of energy output for small-scale wind power generators is the subject of this article. Monthly wind energy production is estimated using the Weibull-representative wind data for a total of 96 months, from 5 different locations in the world. The Weibull parameters are determined based on the wind distribution statistics calculated from the measured data, using the gamma function. The wind data in relative frequency format is obtained from these calculated Weibull parameters. The wind speed data in time-series format and the Weibull-representative wind speed data are used to calculate the wind energy output of a specific wind turbine. The monthly energy outputs calculated from the time-series and the Weibull-representative data are compared. It is shown that the Weibull-representative data estimate the wind energy output very accurately. The overall error in estimation of monthly energy outputs for the total 96 months is 2.79%.     

The potential of a small hydro/photovoltaic hybrid system for electricity generation in FUTO,Nigeria

An evaluation of the potential of a small hydro/PV (SHPV) hybrid system for electricity generation in FUTO, Nigeria is presented. Major components of the hydro and PV systems were considered. The study area electricity load demand for a 10-year period, available hydrological data of the Otamiri River and a 12-year solar radiation data of the study area were used in the study. The obtained results show that at a net head of 3 m, the maximum available hydropower was determined during October as 174.70 kW while the Kaplan turbine with a runner diameter not less than 4.67 m was found to be the most suitable. For the photovoltaic (PV) system, the maximum area, the number of PV modules and the battery bank capacity were determined as 3248 m², 3025 and 98,521,098 Ah, respectively. Thus, a SHPV hybrid system is a viable source of power generation for the study area.     

Optimum depth of grout curtain around pumped storage power cavern based on geological conditions

The main objective of this work was to study the design rationale for the optimum grout curtain around the power cavern of the Rudbar Lorestan pumped storage power plant. This grout curtain will prevent water inflow into the power cavern after Rudbar Dam is impounded. This study was based on a combination of geotechnical investigations, geological investigations, and numerical modeling. The power cavern is located in the Dalan Formation, which consists of limestones and dolomite limestones. Geological features such as faults and major joints in limestones as well as the close proximity of the power cavern to the downstream reservoir increase the hazard associated with water inflow from the reservoir into the power cavern. Because of this close proximity, accurately estimating the water inflow into the cavern is an essential task. Three exploratory boreholes were drilled near the power cavern, and permeability tests (Lugeon tests) were conducted in all boreholes. Records at the boreholes were employed as the main source of data for seepage calculations, and it was determined that the permeability of the limestones is approximately 1.25 × 10^?3 m/s. This study used a finite element model to estimate groundwater inflow into the power cavern after the downstream reservoir is impounded. Results show that without a grout curtain, water would seep into the cavern at a rate of about 0.8–1 m³/s, which would make it difficult to operate the power plant. Accounting for geological conditions such as the Rudbar Fault and fractured limestones, as well as the limitations on construction, a grout curtain was designed. The design calls for a curtain that is about 50 m from the power cavern and extends from 1,735 m.a.s.l. to 10 m below the cavern. Modeling the effect of the grout curtain around the cavern with the finite element method showed that the seepage would decrease to a low rate of 0.1 m³/s with the installation of the curtain.     

Ausbreitung von Kältefahnen im Grundwasser bei Erdwärmesonden

Shallow geothermal energy installations, especially ground source heat pump (GSHP) systems are increasingly being used for air conditioning and temperature control in buildings. Heating applications, for example, result in cold temperature anomalies (cold plumes) in the subsurface. To avoid interactions between adjacent cold plumes, authorities recommend minimum distances of about 10 m between installations. The length of these plumes can be simulated analytically and numerically. The presented analytical solutions are valid for steady-state conditions and consider conduction, convection and dispersion. The results show that the length depends on different parameters, especially flow velocity. The plumes in gravel aquifers become temporarily longer than in less permeable aquifers. Even under average energy extraction rates, they can exceed 10 m in length after one heating period. In the presented example the plume has a length of 10 m after 100 days under a continuous energy extraction rate of 55 W?m^?1. However, these plumes can regenerate quickly. Finally, the analytical results are discussed in a legal context.     

Field performance of a Japanese low energy home relying on renewable energy

This paper describes the construction and evaluation of an experimental low energy home assisted by a hybrid system using natural energy resources and unused energy. The home, for which a ground source heat pump (GSHP) system has been installed, was built on the campus of Hokkaido University, Japan in March 1997. The total floor area of the home is 192 m². This home is super insulated and airtight; the calculated coefficient of heat loss is 0.97 W/m² K. It has various passive strategies including direct solar heat gain and a ventilation system with an exhaust stack. Photovoltaic (PV) modules, wind power and solar collectors are adopted in order to achieve self-sufficiency in electric power and domestic hot water (DHW) supply. A GSHP is used for space heating and cooling. Two vertical steel wells are used as vertical earth heat exchangers (VHE). In summer, there is a floor cooling system using piped cold water from the VHE.Approximately 80% of the home’s total energy was provided by PV modules, solar collectors, as well as underground and exhaust heat. The annual amount of purchased energy during the test period was 12.5% that of a typical home in Hokkaido.     

Roadside PM10 and associated metals in Constantine,Algeria

Samples of particulate matter less than or equal to 10 μm (PM10) were collected every other day using an Airmetrics MiniVol portable air sampler in Constantine, the third largest and most densely populated city of Algeria with a population of 600,000. The main objective of this study was to assess the concentrations of particulate matter (PM) with an aerodynamic diameter ≤10 μm (PM10), and dust-laden trace metals in a residential area with heavy traffic during two months, from 25 March 2010 to 24 May 2010. Furthermore, the present work examines the daily levels of metallic elements Fe, Zn and Cu. The PM10 concentrations ranged from 7.6 to 159.4 μg/m³ during the study period. WHO’s daily PM10 average guide value of 50 μg/m³ was exceeded 10 times over 31 samples. HYSPLIT back trajectories were used to identify the source locations of the pollutants. Rain scavenging of atmospheric particulate matter led to a substantial decrease in PM10 concentrations. During the study period, Zn was detected in one sample at a concentration of 0.78 μg/m³. It is believed that air masses originating from Iceland’s Eyjafjöll volcano may have transported clouds of ashes rich in Zn to the sampling site on that occasion. A maximum of 2.92 μg/m³ of Cu was observed when the volcanic cloud reached the sampling site four times during the corresponding 24-h sampling period.     

Spatial modelling of gaseous emissions from two municipal solid waste dump sites

This paper reports the spatial modelling of gaseous emissions from two municipal solid waste dump sites to determine exposure to landfill gases. The AERMOD modelling software and the Mexican Biogas Model were used, with information from nearby meteorological stations for the period 2015–2016. It was observed that, at one of the dump sites, gas emissions reach populated areas, but in concentrations too low to be detected by the olfactory pathway (benzene <5 µg/m³, toluene and xylene <50 µg/m³). At the second dump site, concentrations are greater; there are no population settlements close by. The highest concentrations of benzene, toluene, xylene and hydrogen sulphide are found within, or around, the dump sites, reaching levels greater than 38 μg/m³ for benzene, 770 μg/m³ for toluene and 237 μg/m³ for xylene.     

Dynamic overset 2D CFD numerical simulation of a small vertical axis wind turbine

ABSTRACT

The environmental friendly sources of power have been explored due to increased environment degradation. In this regard, wind energy may be a viable option. A renewed involvement in Vertical axis wind turbines (VAWT) was found. A wide variety of factors such as the cut-in, cut-out wind speed will decide the beneficence of VAWT as a function of energy production and reliability. In this research work, 2D computational fluid analysis of an aggregate small type of vertical axis wind turbine is performed using pecuniary codes of GAMBIT 2.3 and FLUENT 6.3. At starting, the simulation model and numerical method of small type of vertical axis wind turbine is presented in detail having classical NACA0018, NACA0021 and NACA0025 three-bladed rotor. The result shows that NACA0025 bladed rotor has the highest moment of 2.9195?Nm and power 43.7924?W at a tip speed ratio?=?6.     

Thermal performance analysis of evacuated tubes solar air collector in Indian climate conditions

The thermal performance of one-ended evacuated tubes solar air collector is experimentally investigated during the winter season at NIT Kurukshetra, India [29 ° 58^′(latitude) North and 76 ° 53 ^′ (longitude) East]. The collector consists of 15 one-ended evacuated tubes with different lengths of directional inner aluminium tubes (inserted tubes) and a manifold channel, with air used as a working fluid. The inlet air flows through the directional inner aluminium tubes as a result of forced convection. In this experiment, evacuated tubes are used for producing hot air corresponding to different lengths of directional aluminium tubes without using any intermediate fluid. The temperature of the outlet air depends on the air flow rate, length of the directional aluminium tube and solar intensity. The maximum temperature difference between outlet air and inlet air at solar intensity 904 W/m² was found to be 72.7 °C with a flow rate of 5.06 kg/h and length of 0.83 m.     

Smoke Damage Potentials in Industrial Fire Applications

A methodology is presented for the evaluation of smoke damage contours through the coupling of smoke damage functions, deposition profiles and damage thresholds. Previously developed smoke damage functions and deposition velocities are used to illustrate “far-field” smoke damage potentials both for materials representative of semiconductor fabrication facilities as well as large warehouse storage applications. For semiconductor fabrication, smoke damage associated with leakage current (LC) is important, while smoke staining is of primary interest in warehouse storage. Smoke deposition velocities, a key component to quantifying smoke deposition profiles, were determined in a small (1.0 m³) and large (1,200 m³) enclosure. Both enclosures resulted in comparable values. The velocities ranged from 1.2 to 7.3 × 10^?4 m/s. To determine smoke damage potential contours for semiconductor fabrication facilities, electronic circuit board targets were used. Smoke damage was quantified by LC (i.e., shorting). The average normalized LC values for polyvinylchloride, polycarbonate, and nylon ranged from 0.72 to 6.1 × 10^?4 A m²/g. For warehouse storage facilities, filter targets were used. Smoke damage was quantified by brightness change and odor (i.e., volatile organic compounds, VOC) measurements on the targets. Representative materials were liner board, polystyrene, and polymethyl methacrylate. The smoke damage threshold value for brightness change was 0.012 g/m² and for odor was 0.025 g VOC/m². Resulting contours showed strong radial dependency with distance from the fire/smoke source. Smoke damage reached ~28 m for semiconductor fabrication facilities, while for warehouse storage facilities, it was up to 100 m.     

Wind turbine drives — Test results from the ‘falcon’

A wind turbine drive has been designed and built for full scale trials in order to assess the use of this type of propulsion for commercial craft. This wind turbine rig is fitted to the 5.6m long Blackwater sloop ‘Falcon’.

Test results from this boat are presented over a range of operating wind conditions up to Beaufort force 6 (11.5m/s) for two different wind turbine rotors. Maximum boatspeeds reached were 3.5 knots upwind (in 7.2m/s wind), 5.0 knots across the wind (9.8m/s wind) and 5.2 knots downwind (8m/s wind). The ‘hull speed’ of this boat is around 5.0 knots.     

Analysis of feasibility on heating single family houses in rural areas by using sun and wind energy

Households in Lithuania consume about 1/3 of total final consumption of fuel energy. In order to reduce imports of fossil fuel and emissions of dangerous pollutants, solar energy could be used for the above-mentioned needs. That would require large collector areas and volumes for seasonal heat storage. In wintertime the wind speed velocity is much higher than in summertime in Lithuania. Therefore, it is advisable to study meeting the thermal needs of single family houses by combining use of wind and solar energy. To this end analytical research has been made by using deterministic method. The analysis has been carried out for the case when 1 m² of heated room area requires 0.25 m² of solar collector area and 0.5 m² working area of wind turbine rotor. Heat storage is planned for 24 h. By using such a hybrid system during the heating season 42.6–56.2% of heating needs for space and domestic hot water are satisfied. However, for individual days (especially from May to October) a surplus of generated heat is formed and it reaches about 53.6% of space heating needs per year. This relative surplus of energy could be used for transmitting wind power-plant energy to the electric network or in a household and thermal energy can be used for drying agricultural produce, heating greenhouses, open swimming pools and satisfying other needs.     

桅杆结构风振疲劳的时域分析

对桅杆最易发生疲劳损伤的节点做了应力分析,探讨了修正线性准则在桅杆疲劳寿命计算方面的应用及节点参数对其节点疲劳寿命的影响。在各风向上风速服从Weibull分布的随机风作用下,对桅杆有限元模型进行了时域计算,采用雨流法和修正线性准则得到了节点区焊缝的疲劳寿命。     

New Approaches to Evaluate the Performance of Firefighter Protective Clothing Materials

This paper presents new proposals in the evaluation and determination of the optimum materials suitable for use in the design and development of firefighter protective clothing by simultaneously addressing the conflicting factors of thermal protection [heat transfer index (HTI), radiant heat transfer index (RHTI) and thermal threshold index (TTI)] and anti-heat stress [water vapor resistance (WVR) and total heat loss (THL)]. To achieve this, this paper proposes new indices for the materials, two types of “total performance” indices, which are defined as the sum and the product of the competing factors of thermal protection and anti-heat stress. The results showed that the candidate materials of firefighter protective clothing were easily rated when the new indices were applied. Of five candidate materials viz. A, B, B₁, B₂ and C, the B sample, with values for HTI₂₄?=?13.2?±?0.2 s, RHTI₂₄?=?18.0?±?0.8 s, TTI?=?1132?±?33 J/m², WVR?=?17.5?±?0.3 m² Pa/W and THL?=?266.2?±?4.1 W/m², was found to exhibit the best total performance. However, the methods proposed to the scientific community in this paper have so far been validated on a limited data set only, and will require further validation by a wider group of researchers and with more samples. Lastly, comments on ISO 11999-3:2015 were also made for the further improvement and development of technical standards.