Abstract
This study presents a new wave energy converter that operates in two phases. During the first phase, wave energy is stored, raising a mass up to a design height. During the second phase, the mass goes down. When going down, it compresses air that moves a turbine that drives an electrical generator. Because of this decoupling, generators that move much faster than seawater can be used. This allows using “off-the-shelf” electrical generators. The performance of the proposed design was evaluated via simulations. As the device operates in two phases, a different simulation model was built for each phase. The mass-rising simulation model assumes regular waves. The simulation results suggest that energy harvesting is near the theoretical maximum. Mass falling is braked by air compression. Simulations of this system showed oscillatory behavior. These oscillations are lightly damped by the drag against the walls and air. These oscillations translate into generated power. Therefore, smoothing is needed to avoid perturbing the grid. A possible solution, in the case of farms comprising dozens of these devices, is to delay the generation among individual devices. In this manner, the combined generation can be significantly smoothed.