Abstract
Wave energy converter (WEC) designs are still in nascent stages of development, relative to other renewable energy systems like wind or solar. Many different archetypes of WECs have been developed to extract wave energy in different ways, but there has not been clear convergence on one optimal WEC design type. The design space is still large, with ample opportunity to develop new technologies or improve existing ones. However, the WEC design process often does not efficiently include detailed time-domain results from dynamic simulations due to the required number of design iterations and the heavy computation time. These numerical time-domain simulations can provide more detailed and meaningful descriptions of WECs throughout the design process. Currently, the time-domain simulations are performed near the end of the design process, after the major design parameters have already been set. We present a novel design optimization tool to integrate time-domain modeling in the early stages of WEC design.
This tool includes the results of time-domain simulations in the initial design stage to better predict WEC behavior in each design iteration. The major tradeoff in WEC design is the computation time required to numerically model the device versus the accuracy, or fidelity, of results. The integration of time-domain simulations in this tool meets that tradeoff in the middle, where the computation time has been reduced significantly for faster design iterations, while still providing time-domain results in a dynamic environment. The tool is able to generate a mesh description of a design, calculate the hydrodynamic coefficients, and run hour-long numerical simulations in a matter of minutes. This allows for each design iteration to be more accurately modeled and a more optimized design to be found.
We present a design description of an existing WEC in development by the company IProTech. This device, called the PIP (Pitching Inertial Pump), has a unique PTO without mechanical components, where most WEC technologies struggle with mechanical PTO systems. The platform can be used to adjust different design variables using time-domain results from the wave energy converter simulation tool, WEC-Sim. Different variables, such as the WEC’s geometry, mass distribution, and PTO properties, are adjusted with different design constraints in order to maximize the power output from WEC-Sim. A different design parameterization can be easily substituted into the tool to analyze and design different types of WECs. Optimized designs from this tool will create better WEC designs in the initial design development process and simplify the remaining design, testing, and deployment processes.