Determining optimum tilt angles of photovoltaic panels at typical north-tropical latitudes

An application of renewable energy technology is the installation of photovoltaic systems that generate power without emitting pollutants and requiring no fuel. Solar radiation varies with geographic latitude, season, and time of day due to the various sun positions in the sky. Hence, the problem of designing the optimal tilt angle and the orientation of a solar panel arises for maximizing solar radiation collection at a fixed latitude. An approach of employing sky radiance models for determining optimal tilt angle values of solar collectors with respect to a set of geographic latitudes was conducted by using a data archive of the daily global solar radiation collected by the Italian Institute of ENEA. The results provided a set of tilt angles for winter months that enables a solar panel to absorb the maximum amount of global solar radiation and another set of smaller tilt angle values for summer months, as well. The great difference between these two sets suggested to us to plan semifixed solar panels whose tilt angle can be changed twice a year. The relative gain in solar radiation collectable should not be negligible, as shown in Sec. III. (C) 2009 American Institute of Physics. [DOI: 10.1063/1.3148272]