© 2021 Taylor & Francis Group, LLC.Nowadays renewable energy sources play an important role in partially meeting the global energy demand and protecting the environment. Wind energy technology among the renewable sources is developing rapidly around the World as it becomes a challenging renewable energy technology. One of the latest developed technologies that enable small size wind turbines to operate in the most efficient way is the diffuser augmented wind turbine (DAWT) system utilization. In this study, concentrators involving nozzle-diffuser-flange systems were aimed to be reviewed thoroughly by studying the variety of geometries that are mostly available in the literature. Also, the diffuser augmented wind turbine technologies, from the viewpoint of designs, their aerodynamic characteristics, performances, and efficiencies were reviewed extensively. The benefits obtained from cased wind turbines in terms of wind speed and power coefficient enhancements were analyzed considering a variety of different studies found in the literature.