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This paper presents a comprehensive dynamic model of a proton exchange membrane fuel cell (FC) based on the electrical empirical model. The presented model is useful for online control as well as having suitable accuracy.FC stacks produce a DC voltage with a ratio of 2:1 in output from no-load to full-load. In vehicles that are equipped with FCs, the output voltage of the FC is drastically changed because the power and torque of the vehicle change with the driving cycle. In order to improve the performance of the direct torque control of induction motors, the modular structure of a FC is proposed. This proposed structure guarantees the maximum power point tracking and torque ripple reduction. The validity of the proposed structure is satisfied by simulation results using MATLAB/Simulink software.

Green roof technology has a history that predates the modern era. Many functions of green roofs utilized during human history are analogous to contemporary functions. The justification of the use of green roof technology based on a review of literature shows the multiple and documented benefits that these systems can impart to the urban environment. Green Roofs can save energy, reduce neighborhood temperatures, and protect human health. They have a strong regulating effect on the temperature of underlying roof surfaces and building interiors, reducing the energy needed for building cooling and the effects of the urban heat island effect. Keywords: Green Roofs, Energy Conservation, Heat Transfer, Insulation INTRODUCTIONConsidering rising energy price, its impact on consumption, creating motivation for efficiency and increasing its yield, moved researchers to investigate about plant's effect on energy consumption reduction. In addition, due to increasing in population and lack of adequate land for construction, building density in large cities has increased. This high density has caused lots of negative effects. The urban heat island effect that makes the average temperature in the city is higher than normal, is one of them. This increase in temperature causes an increase in energy consumption for cooling [1].