Abstract
Ocean current energy is a potential renewable energy source that can be developed in Indonesia using tidal turbines. The advantages of ocean current energy as an energy source are that its electricity generation can be predicted, more efficient than wind turbines, and suitable for use in archipelagic countries having many straits with high current speeds such as Indonesia. Research to optimize the performance of tidal turbines has been carried out and shows that the installation of diffusers with brims can increase the performance of tidal turbines. This study’s objective is to analyze the effect of brim height variation on the power coefficient on horizontal axis tidal turbines was carried out and validated the results of numerical studies that had been previously done. To achieve the objective of this study, this experiment was conducted using the 244 cm x 140 cm x 120 cm flowing tank with artificial current propelled by two 15 mm-diameter propellers driven by an electrical motor. Flow straighteners and guide vanes were mounted in the flowing tank to maintain the flow uniform in the test section. In this study, the tip speed ratio value was varied from 1 - 5 and used a brim height of 0.1D and 0.2D at diffuser angles of 10.43° and 15.34°. The results of the study showed that the highest power coefficient value was 45.9% at TSR 2 obtained at a diffuser angle of 10.43° and a brim height of 0.3D.