Review of the Influence of Oceanographic and Geometric Parameters on Oscillating Water Columns

Abstract

Wave energy is one of the most powerful sources of energy on our planet, but its exploitation is difficult. Much current research on renewable energy is focused on how to harness ocean energy. However, wave energy converter (WEC) technology is still immature and how to reach high levels of efficiency is still unknown. In coming years, this field is likely to reach a high level of development, so it is important to continue research on the improvement of the performance of these devices. One of the most important wave energy converters is the oscillating water column (OWC). The main difficulty of OWCs is that they have to provide good rates of hydrodynamic efficiency for many different types of sea states (different periods, heights, wavelengths, etc.). The other big concern is the optimization of the geometric parameters of the device. This research paper is focused on these two big concerns: how oceanographic parameters affect the hydrodynamic behavior of an OWC and its geometric optimization. Different studies about how wave and geometric characteristics affect the performance of an OWC are reviewed and relationships between these and the hydrodynamic performance of an OWC are finally outlined and summed up.

Study of a New Wave Energy Converter with Perturb and Observe Maximum Power Point Tracking Method

“….. δ 1 is the angular acceleration of the main pulley 1, r is the radio of the main pulley 1, c is the gear ratio (high angular velocity/low angular velocity), T b is the torque of each secondary shaft bearing, T g is the torque of the generator and F c01 is the cable tension between the main pulley 1 and the counterweight. If the point absorber and the electric generator are uncoupled, Equation ( 15) is rewritten as Equation (17). J…”

“…The efficiency of the WEC depends mainly on this system; it can be considered as the brain [11] because it can influence the dynamics of the component that interacts with the wave to maximize energy capture. The PTO system is based on a hydraulic [16], pneumatic [17,18] or mechanical system [9,19]; hydraulic and pneumatic components decrease the efficiency of WECs [9]. For this reason, in recent years, the application of the direct drive mechanical system and the direct electrical drive system has increased [11].…”

Constructal Design Applied to an Oscillating Water Column Wave Energy Converter Device under Realistic Sea State Conditions

“…The performance and efficiency of OWC devices depend largely on their geometries and the characteristics of the incident waves [16]. Therefore, it is essential to optimize the design of OWC devices to maximize their power outputs and minimize their costs.…”

“…Therefore, it is essential to optimize the design of OWC devices to maximize their power outputs and minimize their costs. Several studies have conducted investigations regarding the geometry of OWC WEC devices [16][17][18][19], and many have employed the constructal design method for that purpose [20,21]. Ning et al [18] numerically analyzed the hydrodynamic performance of a fixed U-shaped OWC device, evaluating the effects of geometrical parameters, such as the vertical duct height, vertical duct width, and wall thickness.…”

“…Since the wave characteristics of installation sites for OWC WECs are very singular, one of the main difficulties is providing good rates of hydrodynamic efficiency for highly variable sea states [16]. Therefore, the wave parameters of a possible installation site must be evaluated so that they may present a high efficiency.…”