Triboelectric nanogenerator integrated with a simple controlled switch for regularized water wave energy harvesting

Ocean is full of low-frequency,irregular,and widely distributed wave energy,which is suitable as the energy source for maritime Internet of Things(IoTs).Utilizing triboelectric nanogenerators(TENGs)to harvest ocean wave energy and power sensors is proven to be an effective scheme.However,in random ocean waves,the irregular electrical energy output by general TENGs restricts the applications.At present,achieving regularized water wave energy harvesting relies on rather complex mechanical structure designs,which is not conducive to industrialization.In this work,we proposed a novel mechanical controlled TENG(MCTENG)with a simple controlled switch to realize the regularization function.The structural parameters of the MC-TENG are optimized,and the optimal output voltage,output current,and transferred charge respectively reach 1684.2 V,85.4μA,and 389.9 nC,generating a peak power density of 38.46 W·m^(−3)·Hz^(−1).Under real water wave environment,the output of the MC-TENG is regularized and keeps stable regardless of any wave conditions.Moreover,the potential applications of the MC-TENG are demonstrated in powering environmental temperature,humidity,and wind speed sensors.This work renders a simple approach to achieve effective regularized ocean wave energy harvesting,promoting the TENG industrialization toward practical application of maritime IoTs.

Probing the Wave Nature of Light-Matter Interaction

The wave-particle duality of light is a controversial topic in modern physics. In this context, this work highlights the ability of the wave-nature of light on its own to account for the conservation of energy in light-matter interaction. Two simple fundamental properties of light as wave are involved: its period and its power P. The power P depends only on the amplitude of the wave’s electric and magnetic fields (Poynting’s vector), and can easily be measured with a power sensor for visible and infrared lasers. The advantage of such a wave-based approach is that it unveils unexpected effects of light’s power P capable of explaining numerous results published in current scientific literature, of correlating phenomena otherwise considered as disjointed, and of making predictions on ways to employ the electromagnetic (EM) waves which so far are unexplored. In this framework, this work focuses on determining the magnitude of the time interval that, coupled with light’s power P, establishes the energy conserved in the exchange of energy between light and matter. To reach this goal, capacitors were excited with visible and IR lasers at variable average power P. As the result of combining experimental measurements and simulations based on the law of conservation of energy, it was found that the product of the period of the light by its power P fixes the magnitude of the energy conserved in light’s interaction with the capacitors. This finding highlights that the energy exchanged is defined in the time interval equal to the period of the light’s wave. The validity of the finding is shown to hold in light’s interaction with matter in general, e.g. in the photoelectric effect with x-rays, in the transfer of electrons between energy levels in semiconducting interfaces of field effect transistors, in the activation of photosynthetic reactions, and in the generation of action potentials in retinal ganglion cells to enable vision in vertebrates. Finally, the validity of the finding is investigated in the low frequency spectrum of the EM waves by exploring possible consequences in microwave technology, and in harvesting through capacitors the radio waves dispersed in the environment after being used in telecommunications as a source of usable electricity.

A drawstring triboelectric nanogenerator with modular electrodes for harvesting wave energy

The development and utilization of marine blue energy has become the focus of current research.A drawstring triboelectric nanogenerator with modular electrodes(DS-TENG)is proposed to harvest wave energy.Motion displacement and water wave adaptability are improved by using the drawstring structure in the DS-TENG.Furthermore,the modular electrode design is applied to improve the durability and replaceability of the generation units.The rationality of the structure is verified by theoretical analysis,and performance experiments on the fundamental output,displacement and frequency,durability and application are carried out.The DS-TENG can achieve output performance of 98.03 nC,3.63μA,238.50 V and 923.92µW at 150 mm and 1.0 Hz.In addition,the performance drops by 6.11%after 110,000 cycles for DS-TENG durability.This paper will provide reference for the design of TENG that adapts to a wide range of wave heights.

Scalable rolling-structured triboelectric nanogenerator with high power density for water wave energy harvesting toward marine environmental monitoring

In the context of advocating a green and low-carbon era,ocean energy,as a renewable strategic resource,is an important part of planning and building a new energy system.Triboelectric nanogenerator(TENG)arrays provide feasible and efficient routes for large-scale harvesting of ocean energy.In previous work,a spherical rolling-structured TENG with three-dimensional(3D)electrodes based on rolling motion of dielectric pellets was designed and fabricated for effectively harvesting low-frequency water wave energy.In this work,the external shape of the scalable rolling-structured TENG(SR-TENG)and internal filling amount of pellets were mainly optimized,achieving an average power density of 10.08 W∙m^(−3)under regular triggering.In actual water waves,the SR-TENG can deliver a maximum peak power density of 80.29 W∙m^(−3)and an average power density of 6.02 W∙m^(−3),which are much greater than those of most water wave-driven TENGs.Finally,through a power management,an SR-TENG array with eight units was demonstrated to successfully power portable electronic devices for monitoring the marine environment.The SR-TENGs could promote the development and utilization of ocean blue energy,providing a new paradigm for realizing the carbon neutrality goal.

A novel tuned heave plate system for heave motion suppression and energy harvesting on semi-submersible platforms

Deepwater offshore structures such as semi-submersible platforms suffer powerful ocean waves due to their location and site condition. The long distance away from the shore also brings many difficulties to energy supply for the platform operation. How to reduce the response of the platform and convert the wave energy into electrical power is a meaningful topic. In this paper, a tuned heave plate system(THP) is presented and designed to be employed on a semi-submersible platform for heave motion suppression and energy harvesting. This THP system is composed of spring supports, a power take-off system(PTO), and a heave plate. The PTO system is a permanent magnet linear generator(PMLG), which could directly convert the kinetic energy of the heave plate into electronic power. The stiffness of the spring supports is designed based on the principle of the tuned mass damper(TMD). The numerical model of the platform and the THP system is established according to the hydrodynamic analysis results of the platform. The model is tested and modified by scale model tests on the platform in the wave tank. A parameter study, including the size, tuned period, and damping ratio of the THP system, is conducted systematically based on the numerical model. The optimal parameters of the THP are selected due to the maximum heave motion reduction under severe wave conditions in South China Sea. The performance of the semi-submersible with and without the THP system under different wave conditions is analyzed. It is demonstrated that this novel tuned heave plate system could reduce the heave motion of the semi-submersible platform significantly and generate considerable power, which makes the THP system have a broad prospect for development.