This study presents analytical and experimental investigations of a double-pass photovoltaic thermal solar air collector. Photovoltaic thermal collector is a combination of thermal and photovoltaic systems. It generates both thermal and electrical energies simultaneously. An experimental setup of a double-pass photovoltaic thermal solar air collector was designed and fabricated to study the performance over a range of design and operating conditions.; A set of steady-state energy balance equations was formulated for the two air streams, the glass cover, the photovoltaic panel, and the back-plate. These equations were reduced to a set of two differential equations, and a closed-form solution was obtained. Reasonably close agreements between the analytical and experimental results were obtained. This model was used to simulate the performance of larger double-pass photovoltaic thermal system by varying the photovoltaic length, packing factor, air mass flow rate and channel depth. The minimum area of the photovoltaic cell necessary to generate sufficient electrical energy to run the fan at a given mass flow rate was also calculated as a function of time for different configurations of the collector.; Several important relationships between the design and operating conditions were obtained. These relationships affected the performance of the double-pass photovoltaic thermal solar collector. Hence, design curves for the photovoltaic thermal solar collector were developed. The designer would be able to predict the performance of the system using the design curves by selecting the required conditions. This includes the effects of changing the channel depth and air mass flow rate on the global solar radiation, thermal, photovoltaic and combined thermal photovoltaic efficiencies, and temperature rise of the collector.; An economic optimization model was developed to study the effect of combinations of mass flow rates, photovoltaic panel length and channel depth on the cost-benefit ratio of the collector. The user could select the optimum design features that correspond to minimum cost-benefit ratio.
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