Recently, focus has been placed on ocean energy resources because environmental concerns regarding the exploitation of hydrocarbons are increasing. Among the various ocean energy sources, tidal current power (TCP) is recognized as the most promising energy source in terms of predictability and reliability. The enormous energy potential in TCP fields has been exploited by installing TCP systems. The flow speed is the most important factor for power estimation of a tidal current power system. The kinetic energy of the flow is proportional to the cube of the flow’s velocity, and velocity is a critical variable in the performance of the system. Since the duct can accelerate the flow speed, its use could expand the applicable areas of tidal devices to relatively low velocity sites. The inclined angle of the duct and the shapes of inlet and outlet affect the acceleration rates of the flow inside the duct. To investigate the effects of parameters that increase the flow speed, a series of simulations are performed using the commercial computational fluid dynamics (CFD) code ANSYS-CFX. Experimental investigations were conducted using a circulation water channel (CWC). Also, mooring system concepts are investigated using the commercial mooring analysis software WADAM and OrcaFlex. Due to other floating structures operating within a limited area, station-keeping is needed in order to keep the motions of the floating duct structures within permissible limits. In this study, methods for optimizing the mooring system of a floating duct-type tidal current power system in shallow water are investigated. Based on the performance and mooring analysis results of the 10 kW floating duct-type TCP system, a new design for a small capacity floating TCP system is introduced.

Recently, focus has been placed on ocean energy resources because environmental concerns regarding the exploitation of hydrocarbons are increasing. Tidal current power, one of the ocean energy resources, has great potential worldwide due to its high energy density. The flow velocity is the most crucial factor for the power estimation of TCP(Tidal Current Power) system since the kinetic energy of the flow is proportional to the cube of the flow speed. So sufficient inflow speed to generate electricity from the tidal current power is necessary. A duct system can accelerate the flow velocity, which could expand the applicable area of TCP systems to relatively lower velocity sites. The shapes of the inlet and outlet could affect the flow rate inside the duct. To investigate the performance of the duct, various ducts were preliminary designed considering the entire system that is single-point moored TCP system and a series of simulations were carried out using ANSYS-CFX v13.0 CFD software. This study introduces a ducted turbine system that can be moored to a seabed. A performance estimation and comparison of results with conventional tidal converters were summarized in this paper.

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