Effects of non-tracking solar collector orientation on energy production : photovoltaic systems

Abstract

Abstract:

This Master's thesis proposes a new method for calculating the optimum tilt and orientation angle of a fitted solar collector. In addition to using geographical data, this method takes into account the radiation data and weather statistics of prospective locations. This makes the calculations valid not only for certain latitudes, but also for certain radiation and weather conditions.

Calculations were done by estimating the energy production of a given solar array using a sequence of different tilt angles and orientation angles. Special attention was given to shaded solar arrays and arrays made up of photovoltaic modules. Specific radiation and weather data was used for both locations. Also, the different attributes of different phovoltaic modules were taken into consideration.

The proposed method is illustrated with two examples. Two solar arrays in two different locations were chosen: one in Southern Finland in Helsinki (60.12 deg. N, 24.57 deg. E), and the other in Central Finland in Viitasaari (63.07 deg. N, 25.68 deg. E).

The calculations for the solar array in Helsinki, which is in planning stage, take into account the shading caused by row installation. Calculations were made for c-Si PV modules. The optimum tilt angle was calculated as 28.6 deg. and the optimum orientation as 0.1 deg. from south to west.

The array in Viitasaari is an existing one, and the calculated optimum tilt and orientation angles were compared to the actual angles used at the location. The solar collector used there is a semi-transparent a-Si PV module. The optimum tilt angle was calculated as 46.4 deg., and the actual angle at the site was 5 deg. The optimum orientation angle was calculated as 4.3 deg. from south to east, and angle used was 0 deg., i.e. south.