الفهرس 
Introduction and Review of LiteratureOnly 14 pages are availabe for public view
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Abstract
Photovoltaic (PV) technology is recognized as one of the most effective and promising renewable energy sources. The efficiency of a PV system is a function of its operating temperature, which negatively impacts the electrical efficiency as soon as it exceeds 25 °C. In this work, a comparison is performed between the electrical and thermal properties of three traditional polycrystalline solar panels, simultaneously, and under the same weather conditions. The electrical and thermal performances for two photovoltaic thermal (PVT) systems are examined when they are cooled depending on a heat exchanger formed by the copper pipes which integrated with a copper sheet in the back of the PVT. For higher mass flow rates and volume concentrations, an improvement in the PV modules short-circuit current (Isc) and open circuit voltage (Voc) yield and electrical conversion efficiency is achieved. The best enhancements in the PVT electrical conversion efficiency are 15.790% and 15.210% for PVTn at volume concentrations = 0.03% and 0.05%, and mass flow rates = 0.03 and 0.07 Kg/s, respectively. Regarding the 0.05% volume concentration of Al2O3 and flow rate of 0.07 Kg/s, an improvement of 18.59% of the temperature of PVTn panels’ surface over the stand-alone photovoltaic (PV) one has been obtained. The uncooled PV system reached a maximum panel temperature of 75.5 °C at noontime and with an average electrical efficiency of 10.210%.