Search results for "wind speed"
showing 10 items of 126 documents
Influence of the quadratic term in the alongwind stochastic response of SDOF structures
1996
A parametric study, regarding the influence of the quadratic pressure term, which is often neglected in the literature, on the stochastic alongwind response of a single-degree-of-freedom (SDOF) structure subjected to wind action, is presented. The results are reported in terms of percentages of difference in the evaluation of the response, by considering and neglecting the quadratic pressure term. The changing parameters considered are: the terrain drag coefficient, the structure height, the structure natural radian frequency, the structure damping coefficient and the wind reference mean velocity. The response stochastic analysis has been carried out in the time domain, by means of the mome…
An integrated simulation method for building energy performance assessment in urban environments
2012
a b s t r a c t The microclimate around a building, establishing through the interaction with other buildings or the natural environment, is a significant factor in the building energy consumption. This paper presents a method for the quantitative analysis of building energy performance under any given urban contexts by linking the microclimate model ENVI-met to the building energy simulation (BES) program EnergyPlus. The full microclimatic factors such as solar radiation, long wave radiation, air temperature, air humidity, and wind speed have been considered in the proposed scheme. A case study has been conducted to analyze the effects of different microclimatic factors on the energy balan…
Short-term prediction of household electricity consumption: assessing weather sensitivity in a Mediterranean area
2008
Abstract Urban microclimatic variations, along with a rapid reduction of unit cost of air-conditioning (AC) equipments, can be addressed as some of the main causes of the raising residential energy demand in the more developed countries. This paper presents a forecasting model based on an Elman artificial neural network (ANN) for the short-time prediction of the household electricity consumption related to a suburban area. Due to the lack of information about the real penetration of electric appliances in the investigated area and their utilization profiles it was not possible to implement a statistical model to define the weather and climate sensitivities of appliance energy consumption. F…
Linear parameter‐varying modelling and control of an offshore wind turbine with constrained information
2014
This study deals with linear parameter-varying modelling and output-feedback H ∞ control design for an offshore wind turbine. The controller is designed with consideration that not all the information in the feedback loop will be used. This constraint is incorporated into the design procedure. Constrained information means that a special zero-non-zero pattern is forced upon the gain matrix. The constrained controller is obtained based on parameter-dependent Lyapunov functions and formulated in terms of linear-matrix inequalities. Since the functions are dependent on the wind speed and accurate wind speed measurements are rarely available in practice, an extended Kalman filter is used to est…
Monte Carlo simulation for the response analysis of long-span suspended cables under wind loads
2004
This paper presents a time-domain approach for analyzing nonlinear random vibrations of long-span suspended cables under transversal wind. A consistent continuous model of the cable, fully accounting for geometrical nonlinearities inherent in cable behavior, is adopted. The effects of spatial correlation are properly included by modeling wind velocity fluctuation as a random function of time and of a single spatial variable ranging over cable span, namely as a one-variate bi-dimensional (1V-2D) random field. Within the context of a Galerkin`s discretization of the equations governing cable motion, a very efficient Monte Carlo-based technique for second-order analysis of the response is prop…
Impact of wind speed on ventilation performance within a container installed with photovoltaic inverter
2017
Abstract PV inverter needs proper ventilation for reducing the heat dissipation of the electronic components. In this work, a container installed with PV inverter is considered with different configurations of cooling channels within the container for ventilation analysis. Typically, high capacity PV inverters are installed inside the container and therefore inverters, are not experiencing external wind effects and it depends on the configuration of cooling channels. In this work, the main cooling channel is located at the top of the inverter; inlet and outlet ventilation holes are located on the side of cross ventilation. They help in analyzing the cooling design, dependent on site specifi…
Analysis of the maximization of wind turbine energy yield using a continuously variable transmission system
2017
Abstract In this paper, an analytic study of the subject of mechanical power transmission in HAWT wind turbine has been carried out. For the most part, the study analyzes the use of continuously variable transmission (CVT) in order to allow the turbine and the electric generator to couple, allowing in turn, an unremitting transmission ratio adjustment. In low-wind sites, the design criteria suggest an oversizing of the wind turbine in order to generate adequate electrical power even at low wind speed. The proposed solution enhances the space of operating points since it allows the electric generator to release the rotational speed from the turbine one (limited due to structural integrity). …
Experimental characterization of a wind generator prototype for sustainable small wind farms
2016
This paper presents the experimental characterization of a wind turbine prototype used for micro wind farms. The proposed prototype, whose advantages can be summarized in versatility of application, low noise and compactness, can generate 1 kW of rated power for a wind speed equal to 4 m/s. The tests here reported and carried out by means of an experimental test bench confirm that the prototype is well designed and adequate for the purpose of its application.
Multi-step ahead wind speed forecasting using an improved wavelet neural network combining variational mode decomposition and phase space reconstruct…
2017
Abstract Accurate wind speed forecasting is crucial to reliable and secure power generation system. However, the intermittent and unstable nature of wind speed makes it very difficult to be predicted accurately. This paper proposes a novel hybrid model based on variational mode decomposition (VMD), phase space reconstruction (PSR) and wavelet neural network optimized by genetic algorithm (GAWNN) for multi-step ahead wind speed forecasting. In the proposed model, VMD is firstly applied to disassemble the original wind speed series into a number of components in order to improve the overall prediction accuracy. Then, the multi-step ahead forecasting for each component is conducted using GAWNN…
Generalized feed-forward based method for wind energy prediction
2013
Abstract Even though a number of new mathematical functions have been proposed for modeling wind speed probability density distributions, still the Weibull function continues to be the most commonly used model in the literature. Therefore, the parameters of this function are still widely used to obtain typical wind probability density distributions for finding the wind energy potential by researchers, engineers and designers. Once long-term average of Weibull function’s parameters are known, then the probability density distributions can easily be obtained. Artificial neural network (ANN) can be used as alternative to analytical approach as ANN offers advantages such as no required knowledg…