Development of a solar photovoltaic system sizing application for Zimbabwe

To effectively employ solar energy there is need to perform a sizing operation that is optimal and cost effective without compromising on the electricity supply. This study focused on the development of a solar photovoltaic (PV) system sizing application with battery storage that is applicable for all major locations in Zimbabwe. The developed system was applicable for sizing backup systems as well as remote homes in rural areas where access to grid electricity is difficult. In designing the solar system sizing application, a database was integrated with a Visual Basic 6.0 program. The information contained in the integrated database was based on 30 locations in Zimbabwe. Information relating to each of the geographical locations such as average peak sunshine hours values, latitude as well as the insolation values of each place was also included in the code. The sizing procedure consisted of the total load calculation followed by the determination of the solar array size, the tilt angle, inverter size and the charge controller. The load requirements at night were also determined and hence the battery bank was calculated. The application goes ahead to perform a cost analysis in order to determine the average cost per kWh of the generated electricity as well as determine the overall cost of the installation. Results showed that the sizing system developed was able to reduce overdesign installation costs due to generic designs by at least 6%, power losses due to nonoptimal tilt angle by 8% and solar system design time by 85%.