CORRELATION OF WIND PATTERNS USING WEIBULL AND RAYLEIGH MODELS FOR ST.XAVIER SECONDARY SCHOOL, NAIVASHA AND JKUAT SITES

Abstract

The  rapidly  increasing  population  and  industrialization  has  led  to  high  energy  demand.  Juja,  having  a  rapidly growing population  and a major University requires an alternative energy source due to frequent power failure.
This paper analyzed the wind speed characteristics for purposes of determining wind energy potential in Juja and Naivasha using the heights of 10 m and 30 m and for a period of three months. The wind data was recorded in 10 minutes intervals. Mean diurnal and monthly variations were calculated. The wind speed averages for 10 m and 30 m were 2.54 m/s and 3.04 m/s, respectively. The average wind speeds at the two heights were used to calculate wind shear exponent and roughness parameter for Juja site which were 0.1652 and 0.0374 respectively. Weibull scale and shape parameters were obtained using Weibull-fit, Regression and Maximum LikeliHood. The wind speed distribution  was  modeled  using  the  Weibull  and  Rayleigh  probability  distribution  functions.  Power  densities  for different  methods  were  calculated.  Results  obtained  from  Juja  site  were  compared  with  results  acquired  from Naivasha. The mean power densities for Juja  and Naivasha by Weibull model were 12.96 W/m² and 36.52 W/m² respectively. Results by Rayleigh model were 2.82 W/m² and 3.31 W/m². The Weibull -fit and Maximum Likelihood
fitted  best  Juja  site  and  Naivasha  respectively.  Windographer  and  Microsoft  Excel  were   used  to  determine  and generate the functions while WindRose diagrams were used to analyze wind direction. The results will guide the designers on selection of appropriate type of wind turbines for optimum power production.

Key words: Power density, wind distribution models, wind direction, wind speed