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Wind Speed and Energy
Published in Mukund R. Patel, Omid Beik, Wind and Solar Power Systems, 2021
The air density at sea level at 1 atm (14.7 psi) and 60°F is 1.225 kg/m3. Using this as a reference, ρ is corrected for the site-specific temperature and pressure. The temperature and the pressure both vary with the altitude. Their combined effect on the air density is given by the following equation, which is valid up to 6,000 m (20,000 ft) of site elevation above sea level: ρ=ρoe−0.297Hm3048 where Hm is the site elevation in meters.
Natural ventilation and its control
Published in G.J. Levermore, Building Energy Management Systems, 2013
Apart from wind pressure creating natural ventilation, there is also stack ventilation. Air density decreases with increasing absolute temperature. At normal temperature (20°C) and standard atmospheric pressure the density is 1.2 kg m−3, but at other temperatures, t(°C), the general gas law gives the density as ρ=1.2(273+20)(273+t)
Engineered Local Exhaust
Published in James P. Wood, Containment in the Pharmaceutical Industry, 2020
If a careful observation of the dust emitted under force is made, the engineer can use Hemeon’s X-distance approach to help design the control envelope. Determining direction of the emitted airstream and the distance to where the dust is seen to move with random room air currents provides one level of control envelope to be established. Temperature effects must be noted. Note other conditions that will affect calculations for example altitude. Air density decreases with increasing altitude. It is better practice to design for a movement of a mass of air rather than a volume of air when altitude is a factor (usually over 2,000 ft.). It is a mass of air molecules that causes containment.
Analysis and Comparison of Weibull Parameters for Wind Energy Potential Using Different Estimation Methods: A Case Study of Isparta Province in Turkey
Published in Electric Power Components and Systems, 2023
Since MRFO is the most successful method in calculating the Weibull parameters, these parameters were used in the calculation of the wind characteristics of the Isparta province. The mean wind speed (Vm), the most probable wind speed (VMP), the wind speed carrying the highest energy (VmaxE), and the wind power density (P) data for the Isparta province are given in Table 4. Air density data is needed to calculate the wind power of the region. The air density value is inversely proportional to temperature. As the temperature increases, the air density decreases. In this study, the air density value was accepted as 1.04 kg/m3 for the Isparta province, since a general analysis was made. According to the results of the analysis, the month with the highest Vm, VMP, VmaxE, and P is January, and the lowest month is June. Vm ranges from 5.093 to 7.005 m/sec. The P value is between 99.16 and 271.62 W/m2. It is seen that the wind speed and power density are high in the winter months. In summer, these values decrease except for August. When the 3-year data of the province is analyzed, the mean speed is calculated as 5.888 m/sec and the wind power density as 173.72 W/m2.
Multicriteria decision and sensitivity analysis support for optimal airport site locations in Ordu Province, Turkey
Published in Annals of GIS, 2023
H. Ebru Çolak, Tuğba Memişoğlu Baykal, Nihal Genç
Another site selection parameter for the airport is elevation. This concept, referred to as airport altitude in the literature, is the elevation of the highest point of the landing site at the airport above sea level. Unfavourable situations that affect aircraft may occur at airports located at elevations too high. As aircraft go up, the air weakens, and the atmospheric pressure decreases. As a result, the aircraft has difficulty in gaining lift at take-off. Airports with this feature need longer runways in response to the low air pressure problem, and thus an increase in take-off speed is required. In addition, weak, less dense air and low atmospheric pressure make it difficult for aircraft to slow down. This may cause hazards. On the other hand, lower air density causes less friction in the aircraft, which means less fuel at higher altitudes (Horonjeff et al. 2010).
The Temporal Overfitting Problem with Applications in Wind Power Curve Modeling
Published in Technometrics, 2023
Abhinav Prakash, Rui Tuo, Yu Ding
Case Study II is based on thirty wind turbines. These datasets are available at https://github.com/TAMU-AML/Datasets/tree/master/TemporalOverfitting. The input variables are the same as that of the inland turbines in Case Study I. These 30 datasets can be further classified into groups of 10, as the 10 turbines in the same group share the same meteorological tower. The meteorological towers measure wind speed at multiple heights, wind direction, ambient pressure and temperature. The multi-height wind speed measurements are used to calculate the wind shear. Ambient pressure and temperature are used to calculate the air density. Wind direction data are also taken from the meteorological towers. Each of the turbines also measure the wind speed at their nacelle. The data for wind speed and power are collected at individual turbines, and turbine’s wind speed data is used to calculate the turbulence intensity. The first meteorological tower has a slightly longer duration of data than the other two towers; see Table 2.