Impact of Temperature on the Efficiency of Monocrystalline and Polycrystalline Photovoltaic Panels: A Comprehensive Experimental Analysis

The negative effect of the operating temperature over the functioning of photovoltaic panels has become a significant issue in actual energetic context, being studied intensively during last decade. The very high operating temperatures of the photovoltaic panels, even for lower levels of solar radiation, determines a drop of the open circuit voltage, with consequences over the electrical power generated and photovoltaic conversion efficiency. The aim of the study is to investigate experimentally the temperature effect over the efficiency of monocrystalline and polycrystalline photovoltaic panels by using a double climatic chamber and a solar simulation device. Within the experimental program were analyzed two photovoltaic panels, one monocrystalline and another polycrystalline, with the same nominal power of 30 Wp. The double climatic chamber used is composed of two separate rooms, the cold and hot one, while the PV panel is placed as a barrier between them. The study is focused on establishing the effect of raising the temperature of PV panel over electrical parameters: voltage, current and power produced and for efficiency and fill factor. The operating temperature is controlled by the flowing of air on the backside of the PV panel inside the cold room. The simulation of solar radiation was performed by using an equipment compatible with the dimensions and characteristics of the climatic chamber. The level of radiation studied corresponds to a vertical integration of PV panels in building facades. The coefficient of the mean variation of the efficiency with photovoltaic panels’ temperature was -0.52 %/°C, for voltage -0.48 %/°C and for current +0.10 %/°C.