Mapping wind power density for Zimbabwe: a suitable Weibull-parameter calculation method

The two-parameter Weibull probability distribution function is versatile for modelling wind speed frequency distribution and for estimating the energy delivery potential of wind energy systems if its shape and scale parameters, k and c, are correctly determined from wind records. In this study, different methods for determining Weibull k and c from wind speed measurements are reviewed and applied at four sample meteorological stations in Zimbabwe. The appropriateness of each method in modelling the wind data is appraised by its accuracy in predicting the power density using relative deviation and normalised root mean square error. From the methods considered, the graphical method proved to imitate the wind data most closely followed by the standard deviation method. The Rayleigh distribution (k=2 is also generated and compared with the wind speed data. The Weibull parameters were calculated by the graphical method for fourteen stations at which hourly wind speed data was available. These values were then used, with the assistance of appropriate boundary layer models, in the mapping of a wind power density map at 50m hub height for Zimbabwe

Unlocking economic value and sustainable furniture manufacturing through recycling and reuse of sawdust

Abstract: The various stages in the manufacture of furniture, from cutting through processing to polishing, produces a lot of sawdust of varying grades. The extraction and disposal of such waste in a developing country such as Zimbabwe, with no established or sustainable ways to handle waste, is a growing concern, often posing environmental challenges. Research was carried out at a leading furniture manufacturing company in Zimbabwe to establish the quantum of sawdust produced periodically while carrying out experiments to determine parameters such as compressive strength and density for the viable production of briquettes that can either be disposed of economically or used for the company’s fuel requirements. An affordable briquetting machine was designed based on existing briquetting technologies to handle the waste in a sustainable and economic way. The challenges encountered in the disposal of the waste were turned into opportunities. The company will not only enjoy modest income from the waste but will also save on their current waste management costs and easily pay back for the briquetting machine