Effects of partial shading on energy and exergy efficiencies for photovoltaic panels with energy storage

Photovoltaic panels are systems that convert solar energy directly into electrical energy. Photovoltaic (PV) technology has progressed with development of material science in recent years. But the efficiency of the photovoltaic panels is low. There are many parameters that affect the efficiency of photovoltaic panels. These; solar radiation, temperature, shading, dusting, angles of inclination of the panel and cable losses. In this paper is investigated the electrical performance and thermodynamics analysis under the shading shapes and shading ratios of photovoltaics panels which have in 75 W power. Three different cases of shading effects as cell, horizontal and vertical shading at different percentage. Some panel parameters; efficiency, cell temperature, fill factor and power difference are analysed using the current voltage curves for allconditions. The shading makes important effect on energy and exergy efficiencies of the system and the most important effect is formed in case of horizontal shading. The maximum power loss was occurred at the shading rate 100% as 69.92% in cellular, 66.93% in vertical, 99.98% in horizontal shading. The photovoltaic panel temperature has a very important effect on the production of the electric energy of the panel. The energy gains of photovoltaic systems decrease as the panel temperature increases. Energy gains can be increased by using various cooling methods. In the second part, phase change material (FDM) was used to cool both photovoltaic panels and to store waste heat. The effect of shadowing on the performance of the panel with PCM is investigated. 50% horizontal and 50% vertical shading conditions have been tested for PCM systems. Calcium chloride hexahydrate (CaCI2.6H2O) was used as FDM. When the ambient temperature is 32.9 oC , the temperature of the system without PCM is 44.85 oC and the temperature of the system with PCM+PV is 40.73 oC. When the panel is horizontally shaded was occurred maximum power is 1.19 W while maximum power of PCM+PV system is 2.83 W and when the panel is vertically shaded was occurred maximum power is 15.85 W, while maximum power of PCM+PV system is 17.65 W.