In the present study, the aim is to model and optimize the photovoltaic/thermal system (PVT) to achieve the highest thermal and electrical efficiencies by considering the physical characteristics. To model the proposed system, the governing relations were derived by considering the desired variables. Then to use the modeling, the validation of the code was done with a valid source, for which the variables of cell surface temperature, a bottom surface, and output fluid were used. After validation, it was observed that the proposed model has good accuracy to achieve the desired goals. To achieve maximum output power by the cell, open circuit voltage and short circuit current for this system was calculated for one day that has the highest radiation intensity, for which the highest voltage and current are 9.3 V and 6.7 A, respectively. Then, after extraction of voltage and short circuit current for the studied cell, the amount of thermal and electrical efficiencies was determined to be 40% and 10%, respectively. In the next step of this research, optimization is performed to achieve the highest efficiency, which is 67% for this system. تفاصيل المقالة

The ever-increasing growth of the population and their concentration in cities has destructive and often catastrophic effects on natural habitats and human life and exposes cities to painful crises, including environmental and human destruction, which has caused humans to turn to technologies emerging to reduce environmental risks. Blockchain is a new and revolutionary technology in the world's management systems. The blockchain network allows individuals, governments, and organizations to implement any transaction securely on this network. With the Internet of Things expansion and the emergence of the Internet of Vehicles, green smart cities, and integration of these technologies with the blockchain network, human life quality has increased. However, new technical and environmental challenges have emerged by combining IoV applications with the blockchain network in expanding green smart cities. This article examines the concepts and advantages of the blockchain network, and then the applications of IoV in green smart cities are analyzed. Then the technical and environmental challenges of IoV are discussed, and finally, solutions for the environmental and technical challenges are presented. تفاصيل المقالة