Underwater energy harvesting system based on plucked-driven piezoelectrics

Abstract

Today, both the underwater communication technologies and the sensor technology are mature enough to motivate the idea of underwater sensor networks. Underwater wireless sensing systems are envisioned for stand-alone applications and as an addition to cabled systems. For example, cabled ocean observatories are being built on submarine cables to deploy an extensive Fiber-optic network of sensors (cameras, wave sensors and seismometers) covering miles of ocean floor. These cables can support communication access points, very much as cellular base stations are connected to the telephone network, allowing users to move and communicate from places where cables cannot reach. In Figure 1 is illustrated the OBSEA underwater observatory having fiber-optic and power cable for communication with the shore station and acoustic modem for communication with underwater wireless instruments. Figure 1 Diagram of underwater observatory. Shows hybrid communication system, measurement equipment with wireless and wired access in underwater environmentHowever, to turn this idea into reality, one must face the problem of providing powering solutions for long term deployments. The energy requirements of low-power electronics have steadily decreased with advancements in efficient circuitry such that energy harvesting systems can be considered feasible solutions in providing power to self-powered systems. Among the ocean areas where harvestable energy is available, the most interesting ones are the areas with tidal and ocean currents and the shallow water areas with significantly wave-induced oscillatory currents at the sea bottom. Particular, wave-induced oscillatory currents at the sea bottom are interesting for harvesting device because of the body dynamics placed in these areas. The path of water displacement in gravity waves is roughly circular motion. In deep water, the path becoming smaller with depth before finally disappearing as the depth increases beyond the zone of wave disturbance and wave motion does not reach the seabed. In shallow water, the water particles have an elliptical orbit and wave motion is felt at the seabed.In this paper, we present the development of a new harvesting system for underwater energy harvesting. New system configuration and piezoelectric bimorph materials are employed to improve the efficiency of energy conversion. In contrast with the conventional bimorph, resonant, vibrational energy harvester, the plucked-driven piezoelectric harvester shown in Figure 2 comprises two beams. One is a piezoelectric generating beam with a high resonant frequency; the second is a short driving beam, plectra. When the plectra impacts the generating beam, vibration is excited first at the system's coupled vibration frequency and then at the generating beam's higher resonant frequency, producing electrical power.

Internet of Underwater Things and Big Marine Data Analytics—A Comprehensive Survey

“…This can also offer a source of energy in the underwater benthic zone. These systems are based on piezoelectric elements and the energy generated is high enough to power UWSNs and their devices [281].…”

Toward Integrated Large-Scale Environmental Monitoring Using WSN/UAV/Crowdsensing: A Review of Applications, Signal Processing, and Future Perspectives

“…To address the first issue, biofouling protection capabilities have been added to the underwater sensors [113,114], and more advanced flotating buoys have been designed to better support the sensing nodes [115]. The energetic problems have been tackled by using both overwater [116,117] and underwater solar energy harvesting technologies [118] as well as by leveraging the kinematic energy from waves [119]. For underwater communications, acoustic waves represent the mostly adopted technology, even if they still suffer from high attenuation, significant delays in propagation, and fading effects.…”

Energy Harvesting in Underwater Acoustic Wireless Sensor Networks: Design, Taxonomy, Applications, Challenges and Future Directions

“…The authors in [43] argue that the conventional piezoelectric materials generate energy that is dependent on the resonant frequency of the materials. Therefore, such materials require a significant magnitude of vibration to be detected and converted to a significant amount of harvested energy.…”

“…The solar radiations incident on the silicon surface by considering a specific incident angle as well as at some tilt. Three different kind [38]- [42] and piezoelectric materials [43]- [56]. The symbol x is used to represent the unspecified value of a metric.…”