               Dept. of Mechanical & Aerospace Engineering, University of Roma “La Sapienza” Via Eudossiana 18, 00184, Roma, Italy  The paper presents the simulation and analysis of an hybrid PV/Thermal solar collector, a combination of photovoltaic (PV) and solar thermal systems for the simultaneous production of electricity and heat from one integrated component. It is well known that the efficiency of a photovoltaic solar cell is adversely affected if the panel temperature exceeds the design value (typically, a loss of 0.5% results per degree in excess). This led to the idea of constructing a hybrid solar panel in which a coolant circulating on the bottom side of the photovoltaic cells (their non%irradiated side) allows to lower their operating temperature, thereby increasing both their efficiency and their life. The sensible heat of this coolant can be then recovered by generating domestic hot water or contributing to space heating. The plate%and%tube, water cooled PVT analysed in this work is the one that currently displays the most promising market perspectives. It consists of a glass plate, a photovoltaic panel, a metal plate welded on the backside and thin parallel tubes for the circulation of the cooling fluid. The model presented here is based on macroscopic mass% and energy balances of the individual components of the collector, allowing to calculate its electrical output and the outlet water temperature as a function of local solar irradiation and panel geometry data. The thermodynamic model of the PV/Thermal collector has been implemented in the library of a modular object%oriented Process Simulator, Camel%Pro™ and the exergetic performance of the systems has been analyzed and compared with the performance of photovoltaic and thermal solar panel. A detailed analysis of the exergy destruction at component level is also presented, to better assess the distribution of irreversibilities across the process and to gain useful design insight.              ! Photovoltaic modules currently on the market presents a relatively low conversion efficiency (5 to 20% peak, depending on the technology), which means, considering also the percentage of incident energy reflected, that more than 50% of the solar radiation is converted into heat, causing an increase in the overall temperature that produces adverse effects on the solar cells both in terms of permanent damage (occurring due to continuous exposure to high temperatures) and of efficiency. It is well%known that the efficiency of a photovoltaic panel is inversely proportional to the temperature (typically there is a net loss of about 0.5% of peak conversion per degree °K). A possible solution is proposed and analysed in this paper: the original idea is that of developing and fielding a hybrid solar panel (PV/T) where the circulation of a fluid in the bottom side absorbs heat from the cells thereby at once increasing efficiency and reducing wear and tear, while the energy drained from the fluid can be used for thermal applications, such as production of domestic hot water, of water for heating/air conditioning (through an absorption HP) or to heat a swimming pool.  Corresponding Author: claudia.toro@uniroma1.it