Research Topics

Energy Harvesting Mw_uW Overview

The following are some of the research topics. Please see “Funded Projects” for more information.

1. Marine Renewable Energy and Powering the Blue EconomyWeChat Screenshot_20200822181835Marine renewable energy potential in the US is 64% of the total electricity generated from all sources in 2010. Over 53% of the US population lives within 50 miles of a coast, so marine renewable energy offer exceptional opportunity. As reported by DOE, expanding demand for ocean-derived food, materials, energy, and knowledge is driving rapid growth in the emerging “blue economy.” Blue economy industries, such as aquaculture, are moving further offshore to take advantage of the vast scale of the ocean, but moving further offshore requires access to consistent, reliable power untethered to land-based power grids. The term “blue economy” is gaining traction among government, industry, and nonprofits as an organizing principle that captures the interplay between economic, social, and ecological sustainability of the ocean. This interest is fueling investment in next-generation maritime or “blue” technologies.

Quite different from wind energy, the ocean wave energy is concentrated at low frequencies and at low, alternating velocities. Marine renewable energy remains in relative infancy.  One of the most important challenges is the power takeoff (PTO) mechanism, which “…is possibly the single most important element in wave energy technology, and underlies many (possibly most) of the failures to date.” This laboratory seeks revolutionary advance by designing, prototyping, and validating innovative PTO mechanisms for different maritime applications, such as desalination, maritime wireless communication, wave-current hybrid energy harvesting, unmanned underwater vehicle charging. A multiple disciplinary approach is being taken for fundamental research in marine hydrodynamics, mechanical design, vibration dynamics, control system, power electronics, techno-economics and environment assessment. Achievements in this area won the 2014 EPA P3 Award, 2014 Winner of Best Technology Development of Large-Scale Energy Harvesting, 2015 R&D 100 Award, 2019 EPA P3 Award ,2019 Concept Winner in “Waves to Water Prize”. (NSF, EPA, DOE,CRCF,USAID)

2. Bio-Inspired Bi-stable Energy Harvesting for Fish Telemetry Tags 

Picture1This NSF project investigates a self-powered bio-inspired fish tag via (1) novel bio-inspired attachments and bio-inspired bi-stable dynamics with minimal influence on fish life and mobility, and (2) theoretical, numerical and experimental investigations on the bi-stable piezoelectric harvester subjected to multiple excitations by the fish motion and fluid flow to realize a self-powered fish tag. Scientific study of marine life requires to track and monitor fish remotely and continuously. A critical and urgent need of continuous long-life monitoring technologies with sensing capabilities has emerged for various purposes including fish behavior, offshore wind farm site selection, and hydroelectricity power plant operation. We aim to investigate a self-powered strategy and a bio-inspired attachment method for fish tags through energy harvesting from the surrounding fluid and fish maneuvering. In this project, 1) we propose a bio-inspired attachment design by investigating the symbiotic relationship of remoras and sharks. 2) we will develop a bi-stable energy harvester by learning the fast snap-through motion of the Venus flytrap to convert the kinetic energy of fish swimming and fluid flow to electricity for powering fish tags. We will theoretically investigate and experimentally validate the fluid-structure-piezoelectric interaction and snap-through dynamics of the bio-inspired bi-stable energy harvester under multiple excitations. 3) we will conduct experiments on real fish to verify the performance of the self-powered fish tags. This project will enable self-powered electric fish telemetry by solving the fundamental challenge of bio-inspired design and broadband nonlinear energy harvesting under a complex environment. The results will provide a powerful tool for wildlife study and aquatic industry. This is a collaborative research project between two universities and one company: Virginia Tech (L. Zuo, Z. Deng), Stevens Institute of Technology (M. Hajj), and Advanced Telemetry Systems, Inc (P. Kuechle).

3. Energy harvesting from human body to power mobile and wearable devices

The energy stored in human body is equal to the energy stored in 1000 kg of AAA battery [1]. Daily activities consume several hundreds of power. At the same time, mobile devices (such as smart phone) consumes only 1~5W of energy [2]. It is possible to harvest energy from human body to power the mobile and wearable devices. However, conventional energy harvesting devices such as hand crank generators burdens and exhausts the human body. It is desirable for the energy harvesting devices to be low burden and incorporate into everyday activities. Two energy harvesting devices were developed in the lab.

Energy-harvesting backpack

We have developed a mechanical Motion Rectification (MMR) based energy harvesting backpack, which weighs only 1.7 lb. The energy harvesting backpack is able to harvest 3W of power when walking at 3 mph. Treadmill experiments show that MMR backpack have nearly six-fold improvement in bandwidth. MMR backpack can have two- to ten-fold increase in specific power.


Charging cellphone (video)

Powering headlight (video)

Energy harvesting shoes

     With the rapid development of low-power devices, wearable electronics are booming in sports, healthcare, and entertainment industries. Traditional way to charge these devices inevitably interrupts their use. Human walking offers sufficiently harvestable and convertible energy sources that can be harvested to continuously power wearable sensors in health monitoring and low-power devices. In particular, the foot motion could produce large force excitations due to heel strike and leg swing.  This project proposes an embedded piezoelectric footwear energy harvester by exploring the dynamic force excitation in a heel. The harvester is constituted of several piezoelectric stacks integrated in the well-designed and optimized force amplification frames and sandwiched by two heel-shaped aluminum plates. A survey investigation is implemented to disclose the dynamic force distribution in the heel induced by body weight and heel-strike at different walking speeds. An optimal force amplification frame is obtained by parameter optimization to achieve a large force amplification factor and efficient energy transmission. The measured average power of the prototype with six piezoelectric tacks is 9.3 mW/shoe at the walking speed of 3.0 mph (4.8 km/h). The simulated average power of the footwear harvester with four piezoelectric stacks is 20.4 mW/shoe based on the experimentally validated model.


4. Energy-Harvesting Vehicle Shock Absorbers

In the USA there are over 255 million ground vehicles, which consume 170 billion gallons of fuel per year, or 44% of US oil (DOT data 2011).  However, only 10-16% energy of the fuel burned by cars is used to drive the vehicles – to overcome the resistance from road friction and air drag (DOE and EPA data). Besides the thermal inefficiency of the engines, one important mechanism of energy loss in automobiles is the dissipation of kinetic energy during vehicle vibration and motion.Q4

We estimated that for a middle-size vehicle, 100W and 400W of average power is available for harvesting from the regenerative shock absorbers while driving on Class B (good) and C (average) roads at 60 mph, which is comparable with the car alternators (500-600W). And the energy potential for trucks, rail cars, and off-road vehicles is on the order of 1kW-10kW. This represents a potential of 1-6% fuel efficiency increase. The objective is to establish an energy-harvesting vehicle suspension technology to improve the fuel efficiency and to significantly enhance the ride comfort and vehicle safety through self-powered suspension control. We have designed both linear and rotational electromagnetic shock absorbers with high energy density, and demonstrated 15W average and 100 peak power from one shock absorber of a SUV on the smooth paved road.  Our work has been highlighted by several public news media including, PhysOrg, IOPscience, New York Times, MIT Technology Review and Winner of the prestigious R&D 100 Award by the R&D Magazine in 2011. We also won the Award of Best Technology Development of Energy Harvesting in the conference of Energy Harvesting and Storage USA. (NYSERDA, CIT, Ford Motor)

5. Energy Harvesting from the Vibration of Railway Tracks

(PI: Lei Zuo)

Q5The railroad transportation, including freight rail, intercity passenger train, commuter rail and subway, plays a very important role in the economy and quality of life for the people. To facilitate policy makers and transportation agencies to make informed decisions on operating and managing the transportation system, electric infrastructures are necessary along the railway tracks, such as the signal lights, road crossing gates, wireless communication, train and track monitoring, positive train control, etc. Unfortunately, the cost-effective and reliable power supply needed for the electrical infrastructures remains a challenge, since significant portion of the rails are in relative remote areas, in the underground tunnels, or on the bridges, where the energy needed to power electric infrastructure is uneconomical to install and maintain.  This project aims at developing an advanced technology of energy harvesting from railway track vibrations to meet the regional and industry-wide need of access to cost-effective and reliable power supply for the track-side electrical infrastructures of rail transportation. The proposed method is to design and integrate an innovative energy harvesting mechanism, fly wheel, electric generator, power electronics and energy storage to produce high-quality DC power up to hundred watts from the irregular and pulse-like track deflections.  Full-scale prototypes have been developed and demonstrated. This project won the award of Best Application of Energy Harvester and has been covered in many news medias, including ASME Mechanical Magazine. (US DOT/UTRC, NYSERDA, CIT)

6. Energy Harvesting and Control of Wind-Induced Vibration of Tall Buildings

Q3The objective of this project is to develop a dual-functional approach to efficiently harvest utility-scale energy and at the same time to effectively mitigate the wind-induced vibrations of large structures like high-rise buildings. Tall buildings, slender towers, and long bridges, being susceptible to dynamic wind load effects, can experience large vibrations. To reduce these vibrations in a building, a popular approach is to utilize a large mass at the top as a tuned mass damper which absorbs some energy in its own motion and dissipates the rest as wasted heat in a damper. In this project, a unique approach is proposed to provide enhanced structural response suppression by converting the dissipated vibration energy into electricity by using a series of optimally configured electricity-generating tuned mass dampers.

To optimize the performance of the dampers in energy harvesting and structural control, the project will conduct a comprehensive study of the dynamics and energy analysis of structures with proposed tuned mass dampers, will design efficient electromagnetic energy transducers for harvesting and connecting to the building’s or structure’s power grid, and will develop a complete semi-active self-powered vibration control system. The proposed research is multi-disciplinary as it blends concepts of structural, mechanical, power system, and electrical engineering for designing an optimal system for energy harvesting to enhance sustainability in structural designs, and for controlling structures to enhance their safety and reliability. (NSF)

7. Energy-Harvesting on the smart tire

Energy harvesting for the smart tire has been an influential topic for researchers over the past several years.  In this project, we developed an energy harvester for smart tire under modulated noise excitations by taking advantage of self-tuning stochastic resonance with particular application to powering smart tires. Compared to existing tire energy harvesters, it has larger power output and wider bandwidth. The former is achieved by stochastic resonance while the latter is by passively tuning the stochastic resonance frequency to track the time varying rotating speeds of the tire via a centrifugal stiffening effect; thus, the harvester maintains optimal power generation over a wide range of vehicle speed. It is an electromagnetic energy harvester consisting of an inward oriented rotating beam subjected to centrifugal force induced buckling. The compressive centrifugal force induces bistability to the harvester. Maximum power of 45 mW is achieved in the simulation while 1.8mW acheived in the ⅓ scale experiment. The half-power bandwidth of the harvester is around 52~111 km/h (32 mph ~ 70 mph), which corresponds to a typical speed range for a car in general road and highway.  


8. Net-Shape and Scalable Additive Manufacturing for Thermoelectric Waste Heat Recovery Materials and Devices using Selective Laser Melting

Picture5Over 55 percent of the energy consumed in the US is released as waste heat. The waste heat from American automobiles is equivalent to losing over $50 billion each year. Among various waste heat recovery technologies,solid-state thermoelectric generators (TEGs) are a promising strategy to increase energy efficiency, alleviate air pollution, and reduce carbon emissions.
The objective of this project is to develop a novel integrated nanomanufacturing process for high-performance thermoelectric materials and functional devices using the selective laser melting (SLM) based additive manufacturing (AM) method. Specifically, the following hypotheses will be tested: (1) The non-equilibrium conditions produced during the laser-based AM process can introduce numerous nano-defects, nanoscale particles, and abundant multi-scale grain boundaries, which can reduce the thermal conductivity dramatically by phonon scatterings. (2) doped Si or other nano-particles will be used as additive materials in the nanomanufacturing process to improve the mechanical properties, enhance the electrical conductivity, and increase the Seebeck coefficient. (3) The laser-based AM can readily realize the graded doping and variable cross-section areas along the length of the thermoelectric elements with temperate variance to make the best use of the temperature-dependent material properties for achieving high performance thermoelectric devices.

This NSF funded project is collaborative research conducted by Prof. Lei Zuo at Virginia Tech, Prof. Sheng Shen at Carnegie Mellon University, and Prof. Jihui Yang at University of Washington.

9. Thermoelectric Energy Generators for Vehicle Applications: Integrated Design and Manufacturing

 Q6A variety of studies have shown that recovering vehicle waste heat can be successfully used to produce electricity using solid state thermoelectric generators (TEG) to supplement the vehicle’s electrical demands, resulting 5-10% fuel savings.  The exhaust system, however, presents unique challenges for integrating thermoelectric devices, including materials, thermal manage es in a rapid, economical, and industrially scalable manner. The proposed approach is based on the recent progress developed by an interdisciplinary team, including non-equilibrium material synthesis of bulk materials with rapid quenching, thermal spray of thick films, laser micromachining for feature patterning, and integrated thermal and mechanical design. The central concept is to fabricate TE structures directly onto exhaust system components, which will result in excellent interface adhesion between material layers that is intrinsically strong, and with no adhesives or mechanical clamping required. Cylindrical exhaust components are readily fabricated with the process, making integration into existing vehicle exhaust systems straightforward and inexpensive. The non-equilibrium material process is expected to enable high figure-of-merit TE couples economically manufactured from abundant materials at low-cost. (NSF, DOE)

10. Energy harvesting for self-powered wireless through-wall data communication system in nuclear environment

In the nuclear industry many important components, such as nuclear reactor pressure vessels (RPV) and spent fuel storage canisters, exist which are completely enclosed by metal and surrounded by thick concrete walls. Monitoring temperature, pressure, radiation, humidity, structural health, ect. within these enclosed vessels is crucial to ensure the safety of the reactor, and fuel containment safety and security. Thick shielding however presents unique challenges to sensing and instrumentation since these metal enclosures and thick concrete shields block electromagnetic waves preventing the transmission of data wirelessly from internals. Wiring through holes in the vessel walls is undesirable, and generally largely unfeasible. External monitoring for internal health is undesirable, and there is currently no internal sensing and instrumentation system that could provide direct measurements of these critical data, because (1) there is no long-lasting electricity power for the sensor inside the enclosed canisters, (2) one cannot transfer the data out of the enclosed steel canister using wires or RF wireless, and (3) the harsh environment of high temperature (175 °C on the wall) and high radiation inside the enclosed vessel creates challenges for electronics and sensors. Similar sensing needs and challenges exist for the nuclear reactor vessels of Boiling Water Reactors (BWR) and Pressurized Water Reactors (PWR).To combat these issues, we are committed to develop and demonstrate an enabling technology for the data communications for nuclear reactors and fuel cycle facilities using radiation and thermal energy harvesters, through-wall ultrasound communication, and harsh environment electronics. The task of our lab is to produce electrical energy from gamma rays through gamma-ray material heating and build electrical management circuit for the powering system. The package will be able to harvest tens of mW or more power from the nuclear radiations directly. The energy will be stored and used to power sensors and ultrasound data transmission inside the vessels. (DOE)

self powered system

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