Dual-axis tracked vs. fixed PV: Energetic response of one-year testing period in Romania

Abstract

The purpose of the current paper is to present and analyze the energetic results obtained from a stand-alone photovoltaic system, consisting of two differently orientated PV modules, over a period of one year of functioning. One of the modules is being pseudo-equatorially oriented along two axes based on an annual orientation program which will be described in the paper. The second PV module is installed on a fixed and optimally tilted frame orientated towards South. The paper also describes the electrical and the monitoring system used for measuring the parameters of the electrical energy produced. In the end of the paper a comparative analysis is made regarding the energetic response of the two tested photovoltaic systems in the geographical and meteorological conditions of the Braşov, Romania location during three most relevant day types (sunny, normal and cloudy days). Two main conclusions can be stated: firstly, non-deterministic orientation programs need to be developed, able to adapt themselves to the instantaneous ratio between direct and diffuse solar radiation; and secondly, the resistance of the consumer has the main role in transforming the whole incident solar radiation into electricity or only a part of it resulting in the need of using control systems capable of adapting the consumer resistance to the maximal power of the PV module.