Feasibility study for wind power at SAB Newlands
Thesis (MScEng (Mechanical and Mechatronic Engineering))--University of Stellenbosch, 2009.
This paper describes a MEng thesis project for a MEng in Renewable Energy Systems program at the Centre for Renewable Energy Studies at the University of Stellenbosch, South Africa. The aim of this paper was to offer to SAB (South African Breweries), in Cape Town, a feasibility study for the possibilities of the usage of wind energy on site. The small scale wind power technology has a long history and has been in South Africa for more than a hundred years in the form of water pump wind mills. All wind mills have an absolute maximum power output defined by the Betz limit. The choice of a wind turbine depends not only on this, but also on the wind speed distribution, the power curve, the location and financing. The small scale turbines have many different design which are predominantly grouped in horizontal axis (HAWT) and vertical axis (VAWT) machines. The choice of turbine for SAB depends on the available wind energy, the available budget, the available space and the application. The aim of the measurements on site was threefold; find a correlation with existing weather stations in the area like at Cape Town International Airport, propose a turbine for SAB’s budget and research the possibility for installing the turbine on one of the buildings. This is also known as building integrated wind turbines. Wind speeds can increase over buildings due to venturi effects and it could therefore be viable to locate these acceleration zones and install a turbine there. The data analysis shows that the wind above the brewery is very well correlated with the wind at the airport. We can therefore use the average speed values of this station to predict average power production. This leads to the proposal of a 1kW or 3kW turbine from a South African manufacturer: Kestrel. Building integration is however not a good idea. The wind is too turbulent and can therefore not be used. This is mainly caused by the fact that the surroundings of the brewery are too high and irregularly shaped. This makes it difficult for the wind to “lower” in between the buildings and accelerate. The wind turbine for SAB is proposed to be installed on the highest point of the roof and based on the neighbouring average wind speed values. The wind turbine should be connected directly to the brewery’s grid with an inverter and would then solely function as an energy saver. Another important aspect is the promotional value in the energy efficiency strategy of SAB.