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Sample records for biomechanical energy harvester

  1. Development of a biomechanical energy harvester

    OpenAIRE

    Donelan J Maxwell; Naing Veronica; Li Qingguo

    2009-01-01

    Abstract Background Biomechanical energy harvesting–generating electricity from people during daily activities–is a promising alternative to batteries for powering increasingly sophisticated portable devices. We recently developed a wearable knee-mounted energy harvesting device that generated electricity during human walking. In this methods-focused paper, we explain the physiological principles that guided our design process and present a detailed description of our device design with an em...

  2. Biomechanical Energy Harvester Design For Active Prostheses

    Directory of Open Access Journals (Sweden)

    Akın Oğuz Kaptı

    2012-06-01

    Full Text Available One of the factors restricting the functions of active prostheses is limited charge times and weights of the batteries. Therefore, some biomechanical energy harvesting studies are conducted for reducing the dependence on batteries and developing the systems that produce energy by utilizing one's own actions during daily living activities. In this study, as a new approach to meet energy needs of active-controlled lower limb prostheses, the design of a biomechanical energy harvester that produces electrical energy from the movements of the knee joint during gait were carried out. This harvester is composed of the generator, planetary gear system and one-way clutch that transmit just the knee extension. Low weight, low additional metabolic power consumption requirement and high electrical power generation are targeted in design process. The total reduction ratio of the transmission is 104, and the knee joint reaction torque applied by the system is 6 Nm. Average electrical powers that can be obtained are 17 W and 5,8 W for the swing extension phase and the entire cycle, respectively. These values seem to be sufficient for charging the battery units of many prostheses and similar medical systems, and portable electronic devices such as mobile phones, navigation devices and laptops.

  3. Development of a biomechanical energy harvester

    Directory of Open Access Journals (Sweden)

    Donelan J Maxwell

    2009-06-01

    Full Text Available Abstract Background Biomechanical energy harvesting–generating electricity from people during daily activities–is a promising alternative to batteries for powering increasingly sophisticated portable devices. We recently developed a wearable knee-mounted energy harvesting device that generated electricity during human walking. In this methods-focused paper, we explain the physiological principles that guided our design process and present a detailed description of our device design with an emphasis on new analyses. Methods Effectively harvesting energy from walking requires a small lightweight device that efficiently converts intermittent, bi-directional, low speed and high torque mechanical power to electricity, and selectively engages power generation to assist muscles in performing negative mechanical work. To achieve this, our device used a one-way clutch to transmit only knee extension motions, a spur gear transmission to amplify the angular speed, a brushless DC rotary magnetic generator to convert the mechanical power into electrical power, a control system to determine when to open and close the power generation circuit based on measurements of knee angle, and a customized orthopaedic knee brace to distribute the device reaction torque over a large leg surface area. Results The device selectively engaged power generation towards the end of swing extension, assisting knee flexor muscles by producing substantial flexion torque (6.4 Nm, and efficiently converted the input mechanical power into electricity (54.6%. Consequently, six subjects walking at 1.5 m/s generated 4.8 ± 0.8 W of electrical power with only a 5.0 ± 21 W increase in metabolic cost. Conclusion Biomechanical energy harvesting is capable of generating substantial amounts of electrical power from walking with little additional user effort making future versions of this technology particularly promising for charging portable medical devices.

  4. Development of a biomechanical energy harvester

    Science.gov (United States)

    Li, Qingguo; Naing, Veronica; Donelan, J Maxwell

    2009-01-01

    Background Biomechanical energy harvesting–generating electricity from people during daily activities–is a promising alternative to batteries for powering increasingly sophisticated portable devices. We recently developed a wearable knee-mounted energy harvesting device that generated electricity during human walking. In this methods-focused paper, we explain the physiological principles that guided our design process and present a detailed description of our device design with an emphasis on new analyses. Methods Effectively harvesting energy from walking requires a small lightweight device that efficiently converts intermittent, bi-directional, low speed and high torque mechanical power to electricity, and selectively engages power generation to assist muscles in performing negative mechanical work. To achieve this, our device used a one-way clutch to transmit only knee extension motions, a spur gear transmission to amplify the angular speed, a brushless DC rotary magnetic generator to convert the mechanical power into electrical power, a control system to determine when to open and close the power generation circuit based on measurements of knee angle, and a customized orthopaedic knee brace to distribute the device reaction torque over a large leg surface area. Results The device selectively engaged power generation towards the end of swing extension, assisting knee flexor muscles by producing substantial flexion torque (6.4 Nm), and efficiently converted the input mechanical power into electricity (54.6%). Consequently, six subjects walking at 1.5 m/s generated 4.8 ± 0.8 W of electrical power with only a 5.0 ± 21 W increase in metabolic cost. Conclusion Biomechanical energy harvesting is capable of generating substantial amounts of electrical power from walking with little additional user effort making future versions of this technology particularly promising for charging portable medical devices. PMID:19549313

  5. Hybrid Nanogenerator for Concurrently Harvesting Biomechanical and Biochemical Energy

    KAUST Repository

    Hansen, Benjamin J.

    2010-07-27

    Harvesting energy from multiple sources available in our personal and daily environments is highly desirable, not only for powering personal electronics, but also for future implantable sensor-transmitter devices for biomedical and healthcare applications. Here we present a hybrid energy scavenging device for potential in vivo applications. The hybrid device consists of a piezoelectric poly(vinylidene fluoride) nanofiber nanogenerator for harvesting mechanical energy, such as from breathing or from the beat of a heart, and a flexible enzymatic biofuel cell for harvesting the biochemical (glucose/O2) energy in biofluid, which are two types of energy available in vivo. The two energy harvesting approaches can work simultaneously or individually, thereby boosting output and lifetime. Using the hybrid device, we demonstrate a "self-powered" nanosystem by powering a ZnO nanowire UV light sensor. © 2010 American Chemical Society.

  6. Optical HMI with biomechanical energy harvesters integrated in textile supports

    Science.gov (United States)

    De Pasquale, G.; Kim, SG; De Pasquale, D.

    2015-12-01

    This paper reports the design, prototyping and experimental validation of a human-machine interface (HMI), named GoldFinger, integrated into a glove with energy harvesting from fingers motion. The device is addressed to medical applications, design tools, virtual reality field and to industrial applications where the interaction with machines is restricted by safety procedures. The HMI prototype includes four piezoelectric transducers applied to the fingers backside at PIP (proximal inter-phalangeal) joints, electric wires embedded in the fabric connecting the transducers, aluminum case for the electronics, wearable switch made with conductive fabrics to turn the communication channel on and off, and a LED. The electronic circuit used to manage the power and to control the light emitter includes a diodes bridge, leveling capacitors, storage battery and switch made by conductive fabric. The communication with the machine is managed by dedicated software, which includes the user interface, the optical tracking, and the continuous updating of the machine microcontroller. The energetic benefit of energy harvester on the battery lifetime is inversely proportional to the activation time of the optical emitter. In most applications, the optical port is active for 1 to 5% of the time, corresponding to battery lifetime increasing between about 14% and 70%.

  7. Overground vs. treadmill walking on biomechanical energy harvesting: An energetics and EMG study.

    Science.gov (United States)

    Martin, Jean-Paul; Li, Qingguo

    2017-02-01

    A biomechanical energy harvester is a wearable device that generates electricity from human motion. Walking on a treadmill has been used almost exclusively by researchers for studying the energetic effects of biomechanical energy harvesters and wearable robotics. A treadmill provides the advantage of having long duration trials within a stationary motion capture volume. However, no consensus exists on whether the results from treadmill walking accurately represent overground walking. We aim to investigate how a biomechanical energy harvester performs overground compared to on a treadmill by measuring energy expenditure and muscle activity. Participants (n=15) walked both overground and on a treadmill with and without a lower limb-driven biomechanical energy harvester. Energy expenditure was measured using indirect calorimetry and muscle activity was collected with surface electromyograms on seven superficial lower limb muscles. We observed a similar increase in metabolic cost of transport (Δoverground: 0.28±0.24J/kgm, Δtreadmill: 0.30±0.24J/kgm) from normal walking (overground: 2.56±0.33J/kgm, treadmill: 3.39±0.31J/kgm) to harvester walking (overground: 2.83±0.35J/kgm, treadmill: 3.69±0.32J/kgm) in both walking modes (p>0.05). This was accompanied a significant increase in muscle activity of select muscle groups (penergy harvester, treadmill will give similar net increases when compared to a controlled walking condition, such as normal walking, on the same walking surface.

  8. Biomechanical energy harvesting from human motion: theory, state of the art, design guidelines, and future directions

    Directory of Open Access Journals (Sweden)

    Shapiro Amir

    2011-04-01

    Full Text Available Abstract Background Biomechanical energy harvesting from human motion presents a promising clean alternative to electrical power supplied by batteries for portable electronic devices and for computerized and motorized prosthetics. We present the theory of energy harvesting from the human body and describe the amount of energy that can be harvested from body heat and from motions of various parts of the body during walking, such as heel strike; ankle, knee, hip, shoulder, and elbow joint motion; and center of mass vertical motion. Methods We evaluated major motions performed during walking and identified the amount of work the body expends and the portion of recoverable energy. During walking, there are phases of the motion at the joints where muscles act as brakes and energy is lost to the surroundings. During those phases of motion, the required braking force or torque can be replaced by an electrical generator, allowing energy to be harvested at the cost of only minimal additional effort. The amount of energy that can be harvested was estimated experimentally and from literature data. Recommendations for future directions are made on the basis of our results in combination with a review of state-of-the-art biomechanical energy harvesting devices and energy conversion methods. Results For a device that uses center of mass motion, the maximum amount of energy that can be harvested is approximately 1 W per kilogram of device weight. For a person weighing 80 kg and walking at approximately 4 km/h, the power generation from the heel strike is approximately 2 W. For a joint-mounted device based on generative braking, the joints generating the most power are the knees (34 W and the ankles (20 W. Conclusions Our theoretical calculations align well with current device performance data. Our results suggest that the most energy can be harvested from the lower limb joints, but to do so efficiently, an innovative and light-weight mechanical design is

  9. Biomechanical energy harvesting: generating electricity during walking with minimal user effort.

    Science.gov (United States)

    Donelan, J M; Li, Q; Naing, V; Hoffer, J A; Weber, D J; Kuo, A D

    2008-02-08

    We have developed a biomechanical energy harvester that generates electricity during human walking with little extra effort. Unlike conventional human-powered generators that use positive muscle work, our technology assists muscles in performing negative work, analogous to regenerative braking in hybrid cars, where energy normally dissipated during braking drives a generator instead. The energy harvester mounts at the knee and selectively engages power generation at the end of the swing phase, thus assisting deceleration of the joint. Test subjects walking with one device on each leg produced an average of 5 watts of electricity, which is about 10 times that of shoe-mounted devices. The cost of harvesting-the additional metabolic power required to produce 1 watt of electricity-is less than one-eighth of that for conventional human power generation. Producing substantial electricity with little extra effort makes this method well-suited for charging powered prosthetic limbs and other portable medical devices.

  10. Ultra-flexible Piezoelectric Devices Integrated with Heart to Harvest the Biomechanical Energy.

    Science.gov (United States)

    Lu, Bingwei; Chen, Ying; Ou, Dapeng; Chen, Hang; Diao, Liwei; Zhang, Wei; Zheng, Jun; Ma, Weiguo; Sun, Lizhong; Feng, Xue

    2015-11-05

    Power supply for medical implantable devices (i.e. pacemaker) always challenges not only the surgery but also the battery technology. Here, we report a strategy for energy harvesting from the heart motion by using ultra-flexible piezoelectric device based on lead zirconate titanate (PZT) ceramics that has most excellent piezoelectricity in commercial materials, without any burden or damage to hearts. Experimental swine are selected for in vivo test with different settings, i.e. opened chest, close chest and awake from anesthesia, to simulate the scenario of application in body due to their hearts similar to human. The results show the peak-to-peak voltage can reach as high as 3 V when the ultra-flexible piezoelectric device is fixed from left ventricular apex to right ventricle. This demonstrates the possibility and feasibility of fully using the biomechanical energy from heart motion in human body for sustainably driving implantable devices.

  11. A highly shape-adaptive, stretchable design based on conductive liquid for energy harvesting and self-powered biomechanical monitoring.

    Science.gov (United States)

    Yi, Fang; Wang, Xiaofeng; Niu, Simiao; Li, Shengming; Yin, Yajiang; Dai, Keren; Zhang, Guangjie; Lin, Long; Wen, Zhen; Guo, Hengyu; Wang, Jie; Yeh, Min-Hsin; Zi, Yunlong; Liao, Qingliang; You, Zheng; Zhang, Yue; Wang, Zhong Lin

    2016-06-01

    The rapid growth of deformable and stretchable electronics calls for a deformable and stretchable power source. We report a scalable approach for energy harvesters and self-powered sensors that can be highly deformable and stretchable. With conductive liquid contained in a polymer cover, a shape-adaptive triboelectric nanogenerator (saTENG) unit can effectively harvest energy in various working modes. The saTENG can maintain its performance under a strain of as large as 300%. The saTENG is so flexible that it can be conformed to any three-dimensional and curvilinear surface. We demonstrate applications of the saTENG as a wearable power source and self-powered sensor to monitor biomechanical motion. A bracelet-like saTENG worn on the wrist can light up more than 80 light-emitting diodes. Owing to the highly scalable manufacturing process, the saTENG can be easily applied for large-area energy harvesting. In addition, the saTENG can be extended to extract energy from mechanical motion using flowing water as the electrode. This approach provides a new prospect for deformable and stretchable power sources, as well as self-powered sensors, and has potential applications in various areas such as robotics, biomechanics, physiology, kinesiology, and entertainment.

  12. The pizzicato knee-joint energy harvester: characterization with biomechanical data and the effect of backpack load

    Science.gov (United States)

    Pozzi, Michele; Aung, Min S. H.; Zhu, Meiling; Jones, Richard K.; Goulermas, John Y.

    2012-07-01

    The reduced power requirements of miniaturized electronics offer the opportunity to create devices which rely on energy harvesters for their power supply. In the case of wearable devices, human-based piezoelectric energy harvesting is particularly difficult due to the mismatch between the low frequency of human activities and the high-frequency requirements of piezoelectric transducers. We propose a piezoelectric energy harvester, to be worn on the knee-joint, that relies on the plucking technique to achieve frequency up-conversion. During a plucking action, a piezoelectric bimorph is deflected by a plectrum; when released due to loss of contact, the bimorph is free to vibrate at its resonant frequency, generating electrical energy with the highest efficiency. A prototype, featuring four PZT-5H bimorphs, was built and is here studied in a knee simulator which reproduces the gait of a human subject. Biomechanical data were collected with a marker-based motion capture system while the subject was carrying a selection of backpack loads. The paper focuses on the energy generation of the harvester and how this is affected by the backpack load. By altering the gait, the backpack load has a measurable effect on performance: at the highest load of 24 kg, a minor reduction in energy generation (7%) was observed and the output power is reduced by 10%. Both are so moderate to be practically unimportant. The average power output of the prototype is 2.06 ± 0.3 mW, which can increase significantly with further optimization.

  13. Energy harvester

    NARCIS (Netherlands)

    Herder, J.L.; Tolou, N.

    2013-01-01

    Energy harvester comprising a mass (2) that is subjectable to environmental forces for bringing it into the status of a moving mass, and means (5) linked to the mass (2) for converting and storing of energy embodied in the moving mass, which means (5) are arranged for subsequent release of said ener

  14. Human skin based triboelectric nanogenerators for harvesting biomechanical energy and as self-powered active tactile sensor system.

    Science.gov (United States)

    Yang, Ya; Zhang, Hulin; Lin, Zong-Hong; Zhou, Yu Sheng; Jing, Qingshen; Su, Yuanjie; Yang, Jin; Chen, Jun; Hu, Chenguo; Wang, Zhong Lin

    2013-10-22

    We report human skin based triboelectric nanogenerators (TENG) that can either harvest biomechanical energy or be utilized as a self-powered tactile sensor system for touch pad technology. We constructed a TENG utilizing the contact/separation between an area of human skin and a polydimethylsiloxane (PDMS) film with a surface of micropyramid structures, which was attached to an ITO electrode that was grounded across a loading resistor. The fabricated TENG delivers an open-circuit voltage up to -1000 V, a short-circuit current density of 8 mA/m(2), and a power density of 500 mW/m(2) on a load of 100 MΩ, which can be used to directly drive tens of green light-emitting diodes. The working mechanism of the TENG is based on the charge transfer between the ITO electrode and ground via modulating the separation distance between the tribo-charged skin patch and PDMS film. Furthermore, the TENG has been used in designing an independently addressed matrix for tracking the location and pressure of human touch. The fabricated matrix has demonstrated its self-powered and high-resolution tactile sensing capabilities by recording the output voltage signals as a mapping figure, where the detection sensitivity of the pressure is about 0.29 ± 0.02 V/kPa and each pixel can have a size of 3 mm × 3 mm. The TENGs may have potential applications in human-machine interfacing, micro/nano-electromechanical systems, and touch pad technology.

  15. Magnetoelectric Energy Harvesting

    Science.gov (United States)

    2014-11-20

    08-2015 Publication Magnetoelectric Energy Harvesting Peter Finkel et al Naval Undersea Warfare Center Division, Newport 1176 Howell Street, Bldg...NUWC 102287 Distribution A An energy harvesting device for harvesting energy from a moving structure includes a housing allowing transmission of...MAGNETOELECTRIC ENERGY HARVESTING STATEMENT OF GOVERNMENT INTEREST [0001] The invention described herein may be manufactured and used by or for the

  16. Broadband pendulum energy harvester

    Science.gov (United States)

    Liang, Changwei; Wu, You; Zuo, Lei

    2016-09-01

    A novel electromagnetic pendulum energy harvester with mechanical motion rectifier (MMR) is proposed and investigated in this paper. MMR is a mechanism which rectifies the bidirectional swing motion of the pendulum into unidirectional rotation of the generator by using two one-way clutches in the gear system. In this paper, two prototypes of pendulum energy harvester with MMR and without MMR are designed and fabricated. The dynamic model of the proposed MMR pendulum energy harvester is established by considering the engagement and disengagement of the one way clutches. The simulation results show that the proposed MMR pendulum energy harvester has a larger output power at high frequencies comparing with non-MMR pendulum energy harvester which benefits from the disengagement of one-way clutch during pendulum vibration. Moreover, the proposed MMR pendulum energy harvester is broadband compare with non-MMR pendulum energy harvester, especially when the equivalent inertia is large. An experiment is also conducted to compare the energy harvesting performance of these two prototypes. A flywheel is attached at the end of the generator to make the disengagement more significant. The experiment results also verify that MMR pendulum energy harvester is broadband and has a larger output power at high frequency over the non-MMR pendulum energy harvester.

  17. Piezoelectric energy harvesting

    CERN Document Server

    Erturk, Alper

    2011-01-01

    The transformation of vibrations into electric energy through the use of piezoelectric devices is an exciting and rapidly developing area of research with a widening range of applications constantly materialising. With Piezoelectric Energy Harvesting, world-leading researchers provide a timely and comprehensive coverage of the electromechanical modelling and applications of piezoelectric energy harvesters. They present principal modelling approaches, synthesizing fundamental material related to mechanical, aerospace, civil, electrical and materials engineering disciplines for vibration-

  18. Energy harvesting for microsystems

    DEFF Research Database (Denmark)

    Xu, Ruichao

    The purpose of this project is to design and fabricate piezoelectric energy harvesters based on integration of Pb(ZrxTi1-x)O3 (PZT) thick film technology and silicon microtechnology. The fabrication processes are carried out in close collaboration with Meggitt Sensing Systems (MSS) who has...... the unique expertise to screen print piezoelectric thick film layers, thus all screen printing steps are done by MSS while the silicon micromachining is carried out at Danchip facility at DTU. The presented energy harvesters are all based on using piezoelectric thick film operating in the 31-mode to generate...... power when strained. Three archetypes of the numerous fabricated energy harvesters will be presented in detail, they represent three major milestones in this project. The first energy harvester archetype has an unimorph cantilever beam, which consists of a 20 µm silicon layer and 10-30 µm screen printed...

  19. Energy harvesting for microsystems

    Energy Technology Data Exchange (ETDEWEB)

    Ruichao Xu

    2012-05-15

    The purpose of this project is to design and fabricate piezoelectric energy harvesters based on integration of Pb(ZrxTi1-x)O3 (PZT) thick film technology and silicon microtechnology. The fabrication processes are carried out in close collaboration with Meggitt Sensing Systems (MSS) who has the unique expertise to screen print piezoelectric thick film layers, thus all screen printing steps are done by MSS while the silicon micromachining is carried out at Danchip facility at DTU. The presented energy harvesters are all based on using piezoelectric thick film operating in the 31-mode to generate power when strained. Three archetypes of the numerous fabricated energy harvesters will be presented in detail, they represent three major milestones in this project. The first energy harvester archetype has an unimorph cantilever beam, which consists of a 20 {mu}m silicon layer and 10-30 {mu}m screen printed PZT layer, anchored on a silicon frame at one end and attached to a silicon proof mass at the other. Electrodes will cover both side of the PZT layer, so the harvested energy can be collected electrically. The second archetype has a bimorph cantilever beam, which consists of two 15-35 {mu}m PZT layers, anchored on a silicon frame at the one end and attached to a silicon proof mass at the other. Electrodes are deposited below, between and above the two PZT layers. The root mean square (RMS) power output measured on this type of harvesters is as high as 37.1{mu}W at 1 g. The third archetype is similar to the first one, the screen printed PZT layer is replaced by a lead free piezoelectric material, (KxNa1-x)NbO3 (KNN). Some of the major challenges encountered during the development processes are bad adhesion, fragile structures and short circuiting through the PZT layer. All of which have being fully or partially solved in this project. The final energy harvesters are designed to be used in an energy harvester powered wireless sensing system. (Author)

  20. Energy Harvesting via Piezoelectricity

    Directory of Open Access Journals (Sweden)

    Tanvi Dikshit

    2010-01-01

    Full Text Available In the present era, wireless data transmission techniques are commonly used in electronic devices. For powering them connection needs to be made to the power supply through wires else power may be supplied from batteries. Batteries require charging, replacement and other maintenance efforts. For example, in the applications such as villages, border areas, forests, hilly areas, where generally remote controlled devices are used, continuous charging of the microcells is not possible by conventional charging methods .So, some alternative methods needs to be developed to keep the batteries full time charged and to avoid the need of any consumable external energy source to charge the batteries.. To resolve such problems, Energy harvesting technique is proposed as the best alternative. There exists variety of energy harvesting techniques but mechanical energy harvesting happens to be the most prominent. This technique utilizes piezoelectric components where deformations produced by different means are directly converted to electrical charge via piezoelectric effect. Subsequently the electrical energy can be regulated or stored for further use. The proposed work in this research recommends Piezoelectricity as a alternate energy source. The motive is to obtain a pollution-free energy source and to utilize and optimize the energy being wasted. In this paper two important techniques are stressed upon to harness the energy viz Piezoelectric Windmill and Increased Bandwidth Piezoelectric Crystal. Current work also illustrates the working principle of piezoelectric crystal and various sources of vibration for the crystal.

  1. Electromagnetic energy harvester for harvesting acoustic energy

    Indian Academy of Sciences (India)

    FARID U KHAN; IZHAR

    2016-04-01

    This paper reports a suspended coil, electromagnetic acoustic energy harvester (AEH) for extracting acoustical energy. The developed AEH comprises Helmholtz resonator (HR), a wound coil bonded to a flexible membrane and a permanent magnet placed in a magnet holder. The harvester’s performance is analyzed under different sound pressure levels (SPLs) both in laboratory and in real environment. In laboratory, when connected to 50 &Omega load resistance and subjected to an SPL of 100 dB, the AEH generated a peak load voltage of 198.7 mV at the resonant frequency of 319 Hz. When working under the optimum load resistance, the AEH generated an optimum load power of 789.65 &muv. In real environment, the developed AEH produced a maximum voltage of25 mV when exposed to the acoustic noise of a motorcycle and generated an optimum voltage of 60 mV when it is placed in the surroundings of a domestic electrical generator.

  2. Nonlinear energy harvesting

    Energy Technology Data Exchange (ETDEWEB)

    Lallart, Mickael; Guyomar, Daniel, E-mail: mickael.lallart@insa-lyon.fr [LGEF, INSA-Lyon, Universite de Lyon, 8 rue de la Physique, F-69621 (France)

    2011-10-29

    The proliferation of wearable and left-behind devices has raised the issue of powering such systems. While primary batteries have been widely used in order to address this issue, recent trends have focused on energy harvesting products that feature high reliability and low maintenance issues. Among all the ambient sources available for energy harvesting, vibrations and heat have been of significant interest among the research community for small-scale devices. However, the conversion abilities of materials are still limited when dealing with systems featuring small dimensions. The purpose of this paper is to presents an up-to-date view of nonlinear approaches for increasing the efficiency of electromechanical and electrocaloric conversion mechanisms. From the modeling of the operation principles of the different architectures, a comparative analysis will be exposed, emphasizing the advantages and drawbacks of the presented concepts, in terms of maximal output power (under constant vibration magnitude or taking into account the damping effect), load independence, and implementation easiness.

  3. Piezoelectric Energy Harvesting Solutions

    Directory of Open Access Journals (Sweden)

    Renato Caliò

    2014-03-01

    Full Text Available This paper reviews the state of the art in piezoelectric energy harvesting. It presents the basics of piezoelectricity and discusses materials choice. The work places emphasis on material operating modes and device configurations, from resonant to non-resonant devices and also to rotational solutions. The reviewed literature is compared based on power density and bandwidth. Lastly, the question of power conversion is addressed by reviewing various circuit solutions.

  4. Pilot study of manual sugarcane harvesting using biomechanical analysis.

    Science.gov (United States)

    Clementson, C L; Hansen, A C

    2008-07-01

    In many countries, sugar cane harvesting is a very labor-intensive activity in which workers usually become fatigued after manually cutting the cane for a few hours. They need frequent pauses for rest, and they experience sustained injuries from excessive stress on the joints and muscles of the body. The cutting tool and motion involved directly influence the stresses created. A cutting tool that has not been designed by taking into consideration occupational biomechanics can lead to unnecessary strains in the body's muscle system, resulting in injuries. The purpose of this research was to carry out a pilot study of the impact of two common manual sugarcane cutting tools and the cutting posture they induce on the body with the aid of biomechanics. The machete and the cutlass from South Africa and Guyana, respectively, were examined to determine the cutting forces. Using static strength prediction modeling, the body stress levels at the point of cut in the cutting motion were determined. The cutting postures of three subjects were contrasted, their extreme postures were identified, and suggestions were made to improve the ergonomics of the cutting activity. The results of this pilot study showed that the cutlass required less cutting force than the machete because of the slicing cut provided by the curved blade edge of the cutlass. However, the biomechanical analysis indicated that the bent blade of the machete required less flexion of the back and therefore was likely to cause less back fatigue and injury. An improved design of the sugarcane manual harvesting tool should incorporate the bend of the machete to reduce flexion and a curved cutting edge that provides a slicing cut.

  5. Advances in energy harvesting methods

    CERN Document Server

    Elvin, Niell

    2012-01-01

    Advances in Energy Harvesting Methods presents a state-of-the-art understanding of diverse aspects of energy harvesting with a focus on: broadband energy conversion, new concepts in electronic circuits, and novel materials. This book covers recent advances in energy harvesting using different transduction mechanisms; these include methods of performance enhancement using nonlinear effects, non-harmonic forms of excitation and non-resonant energy harvesting, fluidic energy harvesting, and advances in both low-power electronics as well as  material science. The contributors include a brief liter

  6. Nanostructured piezoelectric energy harvesters

    CERN Document Server

    Briscoe, Joe

    2014-01-01

    This book covers a range of devices that use piezoelectricity to convert mechanical deformation into electrical energy and relates their output capabilities to a range of potential applications. Starting with a description of the fundamental principles and properties of piezo- and ferroelectric materials, where applications of bulk materials are well established, the book shows how nanostructures of these materials are being developed for energy harvesting applications. The authors show how a nanostructured device can be produced, and put in context some of the approaches that are being invest

  7. Micro energy harvesting

    CERN Document Server

    Briand, Danick; Roundy, Shad

    2015-01-01

    With its inclusion of the fundamentals, systems and applications, this reference provides readers with the basics of micro energy conversion along with expert knowledge on system electronics and real-life microdevices. The authors address different aspects of energy harvesting at the micro scale with a focus on miniaturized and microfabricated devices. Along the way they provide an overview of the field by compiling knowledge on the design, materials development, device realization and aspects of system integration, covering emerging technologies, as well as applications in power management, e

  8. Waste energy harvesting mechanical and thermal energies

    CERN Document Server

    Ling Bing, Kong; Hng, Huey Hoon; Boey, Freddy; Zhang, Tianshu

    2014-01-01

    Waste Energy Harvesting overviews the latest progress in waste energy harvesting technologies, with specific focusing on waste thermal mechanical energies. Thermal energy harvesting technologies include thermoelectric effect, storage through phase change materials and pyroelectric effect. Waste mechanical energy harvesting technologies include piezoelectric (ferroelectric) effect with ferroelectric materials and nanogenerators. The book aims to strengthen the syllabus in energy, materials and physics and is well suitable for students and professionals in the fields.

  9. Piezoelectric Energy Harvesting for Roadways

    OpenAIRE

    Xiong, Haocheng

    2015-01-01

    Energy harvesting technologies have drawn much attention as an alternative power source of roadway accessories in different scales. Piezoelectric energy harvesting consisting of PZT piezoceramic disks sealed in a protective package is developed in this work to harness the deformation energy of pavement induced by traveling vehicles and generate electrical energy. Six energy harvesters are fabricated and installed at the weigh station on I-81 at Troutville, VA to perform on-site evaluation. T...

  10. Development of an energy harvesting backpack and performance evaluation.

    Science.gov (United States)

    Shepertycky, Michael; Zhang, Jun-Tian; Liu, Yan-Fei; Li, Qingguo

    2013-06-01

    A biomechanical energy harvesting backpack that generates electrical energy during human walking is presented. This device differs from previous designs because it integrates motion from both lower limbs into a single mechanical drive train. The energy harvesting backpack produced an average of 15 W of electricity during walking at a speed of 1.2m/s. It was found that approximately one quarter of the total mechanical work harvested was from the negative work performed during walking. This technology could potentially be used to power portable biomedical devices.

  11. Magnetic Nanocomposite Cilia Energy Harvester

    KAUST Repository

    Khan, Mohammed Asadullah

    2016-02-11

    An energy harvester capable of converting low frequency vibrations into electrical energy is presented. The operating principle, fabrication process and output characteristics at different frequencies are discussed. The harvester is realized by fabricating an array of polydimethylsiloxane (PDMS) - iron nanowire nanocomposite cilia on a planar coil array. Each coil element consists of 14 turns and occupies an area of 600 μm x 600μm. The cilia are arranged in a 12x5 array and each cilium is 250 μm wide and 2 mm long. The magnetic characteristics of the fabricated cilia indicate that the nanowires are well aligned inside of the nanocomposite, increasing the efficiency of energy harvesting. The energy harvester occupies an area of 66.96 mm2 and produces an output r.m.s voltage of 206.47μV, when excited by a 40 Hz vibration of 1 mm amplitude.

  12. Energy Harvesting from Mechanical Shocks Using A Sensitive Vibration Energy Harvester

    OpenAIRE

    Zdenek Hadas; Vojtech Vetiska; Vladislav Singule; Ondrej Andrs; Jiri Kovar; Jan Vetiska

    2012-01-01

    This paper deals with a unique principle of energy harvesting technologies. An energy harvesting device generates electric energy from its surroundings using some kind of energy conversion method. Therefore, the considered energy harvesting device does not consume any fuel or substance. The presented energy harvesting system is used forenergy harvesting of electrical energy from mechanical shocks. The presented energy harvesting system uses a very sensitive vibration energy harvester, which w...

  13. Rotational Electromagnetic Energy Harvesting System

    Science.gov (United States)

    Dinulovic, Dragan; Brooks, Michael; Haug, Martin; Petrovic, Tomislav

    This paper presents development of the rotational electromagnetic energy harvesting transducer. The transducer is driven mechanically by pushing a button; therefore, the mechanical energy will be converted into electrical energy. The energy harvesting (EH) transducer consists of multilayer planar coils embedded in a PCB, multipolar NdFeB hard magnets, and a mechanical system for movement conversion. The EH transducer generate an energy of about 4 mJ at a load of 10 Ω. The maximum open circuit output voltage is as high as 2 V and the maximum short circuit output current is 800 mA.

  14. Harvesting and preparation of cadaveric osseoligamentous lower cervical spine (C2-C7) for biomechanical testing

    OpenAIRE

    Yeh, J; Jackowski, A

    1998-01-01

    Cadaveric osseoligamentous lower cervical spines (C2-C7) are often used in the investigation of spinal biomechanics in vitro. Surprisingly, however, the techniques of harvesting at postmortem and preparation of cadaveric osseoligamentous lower cervical spine for biomechanical testing have not been described in detail. We describe a simple and effective method that can be readily integrated into the routine autopsy procedure. Points on the avoidance of disfiguring the cadaver and damaging the ...

  15. Energy Harvesting Applications of Ionic Polymers

    OpenAIRE

    Martin, Benjamin Ryan

    2005-01-01

    Energy Harvesting Applications of Ionic Polymers Benjamin R. Martin Abstract The purpose of this thesis is the development and analysis of applications for ionic polymers as energy harvesting devices. The specific need is a self-contained energy harvester to supply renewable power harvested from ambient vibrations to a wireless sensor. Ionic polymers were investigated as mechanical to electrical energy transducers. An ionic polymer device was designed to harvest energy from vi...

  16. Energy harvesting devices for harvesting energy from terahertz electromagnetic radiation

    Science.gov (United States)

    Novack, Steven D.; Kotter, Dale K.; Pinhero, Patrick J.

    2012-10-09

    Methods, devices and systems for harvesting energy from electromagnetic radiation are provided including harvesting energy from electromagnetic radiation. In one embodiment, a device includes a substrate and one or more resonance elements disposed in or on the substrate. The resonance elements are configured to have a resonant frequency, for example, in at least one of the infrared, near-infrared and visible light spectra. A layer of conductive material may be disposed over a portion of the substrate to form a ground plane. An optical resonance gap or stand-off layer may be formed between the resonance elements and the ground plane. The optical resonance gap extends a distance between the resonance elements and the layer of conductive material approximately one-quarter wavelength of a wavelength of the at least one resonance element's resonant frequency. At least one energy transfer element may be associated with the at least one resonance element.

  17. Energy Harvesting from Mechanical Shocks Using A Sensitive Vibration Energy Harvester

    Directory of Open Access Journals (Sweden)

    Zdenek Hadas

    2012-11-01

    Full Text Available This paper deals with a unique principle of energy harvesting technologies. An energy harvesting device generates electric energy from its surroundings using some kind of energy conversion method. Therefore, the considered energy harvesting device does not consume any fuel or substance. The presented energy harvesting system is used forenergy harvesting of electrical energy from mechanical shocks. The presented energy harvesting system uses a very sensitive vibration energy harvester, which was developed for an aeronautic application at Brno University of Technology. This energy harvesting system is a complex mechatronic device, which consists of a precise mechanical part, an electromagnetic converter, power electronics (power management and a load (e.g., wireless sensor. The very sensitive vibration energy harvester is capable of usingthe mechanical energy of mechanical shocks and it can harvest useful energy. This energy harvesting system is used with a wireless temperature sensor and measured results are presented in this paper.

  18. Energy-Harvesting Wireless Sensor Networks

    DEFF Research Database (Denmark)

    Fafoutis, Xenofon; Vuckovic, Dusan; Di Mauro, Alessio

    2012-01-01

    Energy Harvesting comprises a promising solution to one of the key problems faced by battery-powered Wireless Sensor Networks, namely the limited nature of the energy supply (finite battery capacity). By harvesting energy from the surrounding environment, the sensors can have a continuous lifetime...... Sensor Networks with energy harvesting capability....

  19. Space still available in energy harvesting workshop

    OpenAIRE

    Brunais, Andrea

    2010-01-01

    A few slots are still open for Virginia Tech's 5th annual energy harvesting workshop March 3 and 4 in Roanoke. Energy harvesting, also known as energy scavenging or power harvesting, refers to the capture of energy from sources such as sun and wind.

  20. High sensitivity fluid energy harvester

    CERN Document Server

    Morarka, Amit

    2016-01-01

    An ambient energy harvesting device was design and fabricated. It can harness kinetic energy of rain droplets and low velocity wind flows. The energy converted into electrical energy by using a single device. The technique used by the device was based on the principles of electromagnetic induction and cantilever. Readily available materials were characterized and used for the fabrication of cantilever. Under the laboratory conditions, water droplets having diameter 4mm and wind with speed 0.5m/s were used as the two distinct sources. Without making any changes in the geometry or the materials used, the device was able to convert kinetic energy from both the sources to provide voltage in the range of 0.7-1VAC. The work was conceptualized to provide an autonomous device which can harness energy from both the renewable energy sources.

  1. Motorcycle waste heat energy harvesting

    Science.gov (United States)

    Schlichting, Alexander D.; Anton, Steven R.; Inman, Daniel J.

    2008-03-01

    Environmental concerns coupled with the depletion of fuel sources has led to research on ethanol, fuel cells, and even generating electricity from vibrations. Much of the research in these areas is stalling due to expensive or environmentally contaminating processes, however recent breakthroughs in materials and production has created a surge in research on waste heat energy harvesting devices. The thermoelectric generators (TEGs) used in waste heat energy harvesting are governed by the Thermoelectric, or Seebeck, effect, generating electricity from a temperature gradient. Some research to date has featured platforms such as heavy duty diesel trucks, model airplanes, and automobiles, attempting to either eliminate heavy batteries or the alternator. A motorcycle is another platform that possesses some very promising characteristics for waste heat energy harvesting, mainly because the exhaust pipes are exposed to significant amounts of air flow. A 1995 Kawasaki Ninja 250R was used for these trials. The module used in these experiments, the Melcor HT3-12-30, produced an average of 0.4694 W from an average temperature gradient of 48.73 °C. The mathematical model created from the Thermoelectric effect equation and the mean Seebeck coefficient displayed by the module produced an average error from the experimental data of 1.75%. Although the module proved insufficient to practically eliminate the alternator on a standard motorcycle, the temperature data gathered as well as the examination of a simple, yet accurate, model represent significant steps in the process of creating a TEG capable of doing so.

  2. Nonlinear Interactions for Broadband Energy Harvesting

    Science.gov (United States)

    2015-04-22

    is one of the most promising strategies for meeting the power requirements while simultaneously reducing the weight load. However, energy harvesting ...summarize, the current state of the art in mechanical energy harvesting is ineffective for many environments. The proposed research explores new...concepts with the potential to offer fundamentally new insights for energy harvesting . I expect this project to provide enabling technological

  3. Sustainably powering wearable electronics solely by biomechanical energy

    Science.gov (United States)

    Wang, Jie; Li, Shengming; Yi, Fang; Zi, Yunlong; Lin, Jun; Wang, Xiaofeng; Xu, Youlong; Wang, Zhong Lin

    2016-09-01

    Harvesting biomechanical energy is an important route for providing electricity to sustainably drive wearable electronics, which currently still use batteries and therefore need to be charged or replaced/disposed frequently. Here we report an approach that can continuously power wearable electronics only by human motion, realized through a triboelectric nanogenerator (TENG) with optimized materials and structural design. Fabricated by elastomeric materials and a helix inner electrode sticking on a tube with the dielectric layer and outer electrode, the TENG has desirable features including flexibility, stretchability, isotropy, weavability, water-resistance and a high surface charge density of 250 μC m-2. With only the energy extracted from walking or jogging by the TENG that is built in outsoles, wearable electronics such as an electronic watch and fitness tracker can be immediately and continuously powered.

  4. Sustainably powering wearable electronics solely by biomechanical energy.

    Science.gov (United States)

    Wang, Jie; Li, Shengming; Yi, Fang; Zi, Yunlong; Lin, Jun; Wang, Xiaofeng; Xu, Youlong; Wang, Zhong Lin

    2016-09-28

    Harvesting biomechanical energy is an important route for providing electricity to sustainably drive wearable electronics, which currently still use batteries and therefore need to be charged or replaced/disposed frequently. Here we report an approach that can continuously power wearable electronics only by human motion, realized through a triboelectric nanogenerator (TENG) with optimized materials and structural design. Fabricated by elastomeric materials and a helix inner electrode sticking on a tube with the dielectric layer and outer electrode, the TENG has desirable features including flexibility, stretchability, isotropy, weavability, water-resistance and a high surface charge density of 250 μC m(-2). With only the energy extracted from walking or jogging by the TENG that is built in outsoles, wearable electronics such as an electronic watch and fitness tracker can be immediately and continuously powered.

  5. Sustainably powering wearable electronics solely by biomechanical energy

    Science.gov (United States)

    Wang, Jie; Li, Shengming; Yi, Fang; Zi, Yunlong; Lin, Jun; Wang, Xiaofeng; Xu, Youlong; Wang, Zhong Lin

    2016-01-01

    Harvesting biomechanical energy is an important route for providing electricity to sustainably drive wearable electronics, which currently still use batteries and therefore need to be charged or replaced/disposed frequently. Here we report an approach that can continuously power wearable electronics only by human motion, realized through a triboelectric nanogenerator (TENG) with optimized materials and structural design. Fabricated by elastomeric materials and a helix inner electrode sticking on a tube with the dielectric layer and outer electrode, the TENG has desirable features including flexibility, stretchability, isotropy, weavability, water-resistance and a high surface charge density of 250 μC m−2. With only the energy extracted from walking or jogging by the TENG that is built in outsoles, wearable electronics such as an electronic watch and fitness tracker can be immediately and continuously powered. PMID:27677971

  6. Wideband Piezomagnetoelastic Vibration Energy Harvesting

    DEFF Research Database (Denmark)

    Lei, Anders; Thomsen, Erik Vilain

    2014-01-01

    This work presents a small-scale wideband piezomagnetoelastic vibration energy harvester (VEH) aimed for operation at frequencies of a few hundred Hz. The VEH consists of a tape-casted PZT cantilever with thin sheets of iron foil attached on each side of the free tip. The wideband operation...... softening effect. In linear operation (without magnets) the harvester generates a RMS power of 141 μW/g2 at 588 Hz with a relative bandwidth of 3.8% over a 100 kΩ load resistor. When operated with one magnet ideally positioned opposite the cantilever, a RMS power of 265 μW/g2 is generated at 270 Hz...

  7. Ocean Wave Energy Harvesting Devices

    Science.gov (United States)

    2008-01-01

    limited life due to size-weight constraints - Market opportunity exists with Navy for AUV, UUV applications +Gateway buoy L Energy harvester TDY...and commercial markets . 9.4 Scientific and Technical Results and Accomplishments Results of the effort in relation to program objectives 1. A device...C:l 2 .- 1 cc.c. 4-’I U))( 0o 00 LD, o... ....4 - ... . .... . . .. .. . .. . ; ..][ o V n) 0 L-4-’ Ncco 4-0 ) UU -- a),a U) 1X1 ~ cu a0 cU w4 0 C

  8. Microelectronic circuit design for energy harvesting systems

    CERN Document Server

    Di Paolo Emilio, Maurizio

    2017-01-01

    This book describes the design of microelectronic circuits for energy harvesting, broadband energy conversion, new methods and technologies for energy conversion. The author also discusses the design of power management circuits and the implementation of voltage regulators. Coverage includes advanced methods in low and high power electronics, as well as principles of micro-scale design based on piezoelectric, electromagnetic and thermoelectric technologies with control and conditioning circuit design. Provides a single-source reference to energy harvesting and its applications; Serves as a practical guide to microelectronics design for energy harvesting, with application to mobile power supplies; Enables readers to develop energy harvesting systems for wearable/mobile electronics.

  9. Characterization of Piezoelectric Energy Harvesting MEMS

    Science.gov (United States)

    2015-12-01

    possibilities of using solar power and the piezoelectric effect to harvest energy [12]. The design goal was to develop an energy harvester with a resonant...configurations with power conditioning circuits was explored using LTSPICE IV simulation software and the internal impedance of the piezoelectric energy ...supply a driving voltage to the power amplifier and measure the phase and output voltage of the piezoelectric energy harvester and the accelerometer

  10. Triboelectric Nanogenerators for Blue Energy Harvesting.

    Science.gov (United States)

    Khan, Usman; Kim, Sang-Woo

    2016-07-26

    Blue energy in the form of ocean waves offers an enormous energy resource. However, it has yet to be fully exploited in order to make it available for the use of mankind. Blue energy harvesting is a challenging task as the kinetic energy from ocean waves is irregular in amplitude and is at low frequencies. Though electromagnetic generators (EMGs) are well-known for harvesting mechanical kinetic energies, they have a crucial limitation for blue energy conversion. Indeed, the output voltage of EMGs can be impractically low at the low frequencies of ocean waves. In contrast, triboelectric nanogenerators (TENGs) are highly suitable for blue energy harvesting as they can effectively harvest mechanical energies from low frequencies (blue energy harvesting. In this Perspective, we describe some of the recent progress and also address concerns related to durable packaging of TENGs in consideration of harsh marine environments and power management for an efficient power transfer and distribution for commercial applications.

  11. Pyroelectric Quantum Well Energy Harvesters Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose the investigation of pyroelectric energy harvesters with enhanced efficiencies through quantum wells induced by a multilayer design.  Pyroelectric...

  12. Information Capacity of Energy Harvesting Sensor Nodes

    CERN Document Server

    Rajesh, R

    2010-01-01

    Sensor nodes with energy harvesting sources are gaining popularity due to their ability to improve the network life time and are becoming a preferred choice supporting 'green communication'. We study such a sensor node with an energy harvesting source and compare various architectures by which the harvested energy is used. We find its Shannon capacity when it is transmitting its observations over an AWGN channel and show that the capacity achieving energy management policy is the same as the throughput optimal policy. We also obtain the capacity for the system with energy inefficiencies in storage and an achievable rate when energy conserving sleep-wake modes are supported.

  13. Complete Charging for Piezoelectric Energy Harvesting System

    Institute of Scientific and Technical Information of China (English)

    樊康旗; 徐春辉; 王卫东

    2014-01-01

    Under an in-phase assumption, the complete charging for an energy harvesting system is studied, which consists of a piezoelectric energy harvester (PEH), a bridge rectifier, a filter capacitor, a switch, a controller and a rechargeable battery. For the transient charging, the results indicate that the voltage across the filter capacitor increases as the charging proceeds, which is consistent with that reported in the literature. However, a new finding shows that the charging rate and energy harvesting efficiency decrease over time after their respective peak values are acquired. For the steady-state charging, the results reveal that the energy harvesting efficiency can be adjusted by altering the critical charging voltage that controls the transition of the system. The optimal energy harvesting efficiency is limited by the optimal efficiency of the transient charging. Finally, the relationship between the critical charging voltage and the equivalent resistance of the controller and rechargeable battery is established explicitly.

  14. Thermal Energy Harvesting from Wildlife

    Science.gov (United States)

    Woias, P.; Schule, F.; Bäumke, E.; Mehne, P.; Kroener, M.

    2014-11-01

    In this paper we present the measurement of temperature differences between the ambient air and the body temperature of a sheep (Heidschnucke) and its applicability for thermoelectric energy harvesting from livestock, demonstrated via the test of a specially tailored TEG system in a real-life experiment. In three measurement campaigns average temperature differences were found between 2.5 K and 3.5 K. Analytical models and FEM simulations were carried out to determine the actual thermal resistance of the sheep's fur from comparisons with the temperature measurements. With these data a thermoelectric (TEG) generator was built in a thermally optimized housing with adapted heats sink. The whole TEG system was mounted to a collar, including a data logger for recording temperature and TEG voltage. First measurements at the neck of a sheep were accomplished, with a calculated maximal average power output of 173 μW at the TEG. Taking the necessity of a low-voltage step-up converter into account, an electric output power of 54 μW is available which comes close to the power consumption of a low-power VHF tracking system.

  15. Energy harvesting solar, wind, and ocean energy conversion systems

    CERN Document Server

    Khaligh, Alireza

    2009-01-01

    Also called energy scavenging, energy harvesting captures, stores, and uses ""clean"" energy sources by employing interfaces, storage devices, and other units. Unlike conventional electric power generation systems, renewable energy harvesting does not use fossil fuels and the generation units can be decentralized, thereby significantly reducing transmission and distribution losses. But advanced technical methods must be developed to increase the efficiency of devices in harvesting energy from environmentally friendly, ""green"" resources and converting them into electrical energy.Recognizing t

  16. Piezoelectric energy harvesting computer controlled test bench

    Science.gov (United States)

    Vázquez-Rodriguez, M.; Jiménez, F. J.; de Frutos, J.; Alonso, D.

    2016-09-01

    In this paper a new computer controlled (C.C.) laboratory test bench is presented. The patented test bench is made up of a C.C. road traffic simulator, C.C. electronic hardware involved in automating measurements, and test bench control software interface programmed in LabVIEW™. Our research is focused on characterizing electronic energy harvesting piezoelectric-based elements in road traffic environments to extract (or "harvest") maximum power. In mechanical to electrical energy conversion, mechanical impacts or vibrational behavior are commonly used, and several major problems need to be solved to perform optimal harvesting systems including, but no limited to, primary energy source modeling, energy conversion, and energy storage. It is described a novel C.C. test bench that obtains, in an accurate and automatized process, a generalized linear equivalent electrical model of piezoelectric elements and piezoelectric based energy store harvesting circuits in order to scale energy generation with multiple devices integrated in different topologies.

  17. Hybrid piezoelectric energy harvesting transducer system

    Science.gov (United States)

    Xu, Tian-Bing (Inventor); Jiang, Xiaoning (Inventor); Su, Ji (Inventor); Rehrig, Paul W. (Inventor); Hackenberger, Wesley S. (Inventor)

    2008-01-01

    A hybrid piezoelectric energy harvesting transducer system includes: (a) first and second symmetric, pre-curved piezoelectric elements mounted separately on a frame so that their concave major surfaces are positioned opposite to each other; and (b) a linear piezoelectric element mounted separately on the frame and positioned between the pre-curved piezoelectric elements. The pre-curved piezoelectric elements and the linear piezoelectric element are spaced from one another and communicate with energy harvesting circuitry having contact points on the frame. The hybrid piezoelectric energy harvesting transducer system has a higher electromechanical energy conversion efficiency than any known piezoelectric transducer.

  18. Power Electronics, Energy Harvesting and Renewable Energies Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — The research in the Power Electronics, Energy Harvesting and Renewable Energies Laboratory (PEHREL) is mainly focused on investigation, modeling, simulation, design,...

  19. Hybrid energy harvesting using active thermal backplane

    Science.gov (United States)

    Kim, Hyun-Wook; Lee, Dong-Gun

    2016-04-01

    In this study, we demonstrate the concept of a new hybrid energy harvesting system by combing solar cells with magneto-thermoelectric generator (MTG, i.e., thermal energy harvesting). The silicon solar cell can easily reach high temperature under normal operating conditions. Thus the heated solar cell becomes rapidly less efficient as the temperature of solar cell rises. To increase the efficiency of the solar cell, air or water-based cooling system is used. To surpass conventional cooling devices requiring additional power as well as large working space for air/water collectors, we develop a new technology of pairing an active thermal backplane (ATB) to solar cell. The ATB design is based on MTG technology utilizing the physics of the 2nd order phase transition of active ferromagnetic materials. The MTG is cost-effective conversion of thermal energy to electrical energy and is fundamentally different from Seebeck TEG devices. The ATB (MTG) is in addition to being an energy conversion system, a very good conveyor of heat through both conduction and convection. Therefore, the ATB can provide dual-mode for the proposed hybrid energy harvesting. One is active convective and conductive cooling for heated solar cell. Another is active thermal energy harvesting from heat of solar cell. These novel hybrid energy harvesting device have potentially simultaneous energy conversion capability of solar and thermal energy into electricity. The results presented can be used for better understanding of hybrid energy harvesting system that can be integrated into commercial applications.

  20. Flow Energy Piezoelectric Bimorph Nozzle Harvester

    Science.gov (United States)

    Sherrit, Stewart (Inventor); Walkemeyer, Phillip E. (Inventor); Hall, Jeffrey L. (Inventor); Lee, Hyeong Jae (Inventor); Colonius, Tim (Inventor); Tosi, Phillipe (Inventor); Kim, Namhyo (Inventor); Sun, Kai (Inventor); Corbett, Thomas Gary (Inventor); Arrazola, Alvaro Jose (Inventor)

    2016-01-01

    A flow energy harvesting device having a harvester pipe includes a flow inlet that receives flow from a primary pipe, a flow outlet that returns the flow into the primary pipe, and a flow diverter within the harvester pipe having an inlet section coupled to the flow inlet, a flow constriction section coupled to the inlet section and positioned at a midpoint of the harvester pipe and having a spline shape with a substantially reduced flow opening size at a constriction point along the spline shape, and an outlet section coupled to the constriction section. The harvester pipe may further include a piezoelectric structure extending from the inlet section through the constriction section and point such that the fluid flow past the constriction point results in oscillatory pressure amplitude inducing vibrations in the piezoelectric structure sufficient to cause a direct piezoelectric effect and to generate electrical power for harvesting.

  1. Energy harvesting for dielectric elastomer sensing

    Science.gov (United States)

    Anderson, Iain A.; Illenberger, Patrin; O'Brien, Ben M.

    2016-04-01

    Soft and stretchy dielectric elastomer (DE) sensors can measure large strains on robotic devices and people. DE strain measurement requires electric energy to run the sensors. Energy is also required for information processing and telemetering of data to phone or computer. Batteries are expensive and recharging is inconvenient. One solution is to harvest energy from the strains that the sensor is exposed to. For this to work the harvester must also be wearable, soft, unobtrusive and profitable from the energy perspective; with more energy harvested than used for strain measurement. A promising way forward is to use the DE sensor as its own energy harvester. Our study indicates that it is feasible for a basic DE sensor to provide its own power to drive its own sensing signal. However telemetry and computation that are additional to this will require substantially more power than the sensing circuit. A strategy would involve keeping the number of Bluetooth data chirps low during the entire period of energy harvesting and to limit transmission to a fraction of the total time spent harvesting energy. There is much still to do to balance the energy budget. This will be a challenge but when we succeed it will open the door to autonomous DE multi-sensor systems without the requirement for battery recharge.

  2. Harvesting Vibrational Energy Using Material Work Functions

    Science.gov (United States)

    Varpula, Aapo; Laakso, Sampo J.; Havia, Tahvo; Kyynäräinen, Jukka; Prunnila, Mika

    2014-01-01

    Vibration energy harvesters scavenge energy from mechanical vibrations to energise low power electronic devices. In this work, we report on vibration energy harvesting scheme based on the charging phenomenon occurring naturally between two bodies with different work functions. Such work function energy harvester (WFEH) is similar to electrostatic energy harvester with the fundamental distinction that neither external power supplies nor electrets are needed. A theoretical model and description of different operation modes of WFEHs are presented. The WFEH concept is tested with macroscopic experiments, which agree well with the model. The feasibility of miniaturizing WFEHs is shown by simulating a realistic MEMS device. The WFEH can be operated as a charge pump that pushes charge and energy into an energy storage element. We show that such an operation mode is highly desirable for applications and that it can be realised with either a charge shuttle or with switches. The WFEH is shown to give equal or better output power in comparison to traditional electrostatic harvesters. Our findings indicate that WFEH has great potential in energy harvesting applications. PMID:25348004

  3. Harvesting vibrational energy using material work functions.

    Science.gov (United States)

    Varpula, Aapo; Laakso, Sampo J; Havia, Tahvo; Kyynäräinen, Jukka; Prunnila, Mika

    2014-10-28

    Vibration energy harvesters scavenge energy from mechanical vibrations to energise low power electronic devices. In this work, we report on vibration energy harvesting scheme based on the charging phenomenon occurring naturally between two bodies with different work functions. Such work function energy harvester (WFEH) is similar to electrostatic energy harvester with the fundamental distinction that neither external power supplies nor electrets are needed. A theoretical model and description of different operation modes of WFEHs are presented. The WFEH concept is tested with macroscopic experiments, which agree well with the model. The feasibility of miniaturizing WFEHs is shown by simulating a realistic MEMS device. The WFEH can be operated as a charge pump that pushes charge and energy into an energy storage element. We show that such an operation mode is highly desirable for applications and that it can be realised with either a charge shuttle or with switches. The WFEH is shown to give equal or better output power in comparison to traditional electrostatic harvesters. Our findings indicate that WFEH has great potential in energy harvesting applications.

  4. Materials in energy conversion, harvesting, and storage

    CERN Document Server

    Lu, Kathy

    2014-01-01

    First authored book to address materials' role in the quest for the next generation of energy materials Energy balance, efficiency, sustainability, and so on, are some of many facets of energy challenges covered in current research. However, there has not been a monograph that directly covers a spectrum of materials issues in the context of energy conversion, harvesting and storage. Addressing one of the most pressing problems of our time, Materials in Energy Conversion, Harvesting, and Storage illuminates the roles and performance requirements of materials in energy an

  5. Energy Harvesting Wireless Strain Networks Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Prime Research LC (PPLC) and Virginia Tech (VT) propose to develop an energy harvesting wireless strain node technology that utilizes single-crystal piezoelectric...

  6. Energy harvesting with functional materials and microsystems

    CERN Document Server

    Bhaskaran, Madhu; Iniewski, Krzysztof

    2013-01-01

    For decades, people have searched for ways to harvest energy from natural sources. Lately, a desire to address the issue of global warming and climate change has popularized solar or photovoltaic technology, while piezoelectric technology is being developed to power handheld devices without batteries, and thermoelectric technology is being explored to convert wasted heat, such as in automobile engine combustion, into electricity. Featuring contributions from international researchers in both academics and industry, Energy Harvesting with Functional Materials and Microsystems explains the growi

  7. Triple Hybrid Energy Harvesting Interface Electronics

    Science.gov (United States)

    Uluşan, H.; Chamanian, S.; Pathirana, W. M. P. R.; Zorlu, Ö.; Muhtaroğlu, A.; Külah, H.

    2016-11-01

    This study presents a novel triple hybrid system that combines simultaneously generated power from thermoelectric (TE), vibration-based electromagnetic (EM) and piezoelectric (PZT) harvesters for a relatively high power supply capability. In the proposed solution each harvesting source utilizes a distinct power management circuit that generates a DC voltage suitable for combining the three parallel supplies. The circuits are designed and implemented in 180 nm standard CMOS technology, and are terminated with a schottky diode to avoid reverse current flow. The harvested AC signal from the EM harvester is rectified with a self-powered AC-DC doubler, which utilizes active diode structures to minimize the forward- bias voltage drop. The PZT interface electronics utilizes a negative voltage converter as the first stage, followed by synchronous power extraction and DC-to-DC conversion through internal switches, and an external inductor. The ultra-low voltage DC power harvested by the TE generator is stepped up through a charge-pump driven by an LC oscillator with fully- integrated center-tapped differential inductors. Test results indicate that hybrid energy harvesting circuit provides more than 1 V output for load resistances higher than 100 kΩ (10 μW) where the stand-alone harvesting circuits are not able to reach 1 V output. This is the first hybrid harvester circuit that simultaneously extracts energy from three independent sources, and delivers a single DC output.

  8. Energy Harvesting By Optimized Piezo Transduction Mechanism

    CERN Document Server

    Boban, Bijo; Satheesh, U; Devaprakasam, D

    2014-01-01

    We report generation of electrical energy from nonlinear mechanical noises available in the ambient environment using optimized piezo transduction mechanisms. Obtaining energy from an ambient vibration has been attractive for remotely installed standalone microsystems and devices. The mechanical noises in the ambient environment can be converted to electrical energy by a piezo strip based on the principle of piezoelectric effect. In this work, we have designed and developed a standalone energy harvesting module based on piezo transduction mechanisms. Using this designed module we harvested noise energy and stored electrical energy in a capacitor. Using NI-PXI workstation with a LabVIEW programming, the output voltage of the piezo strip and voltage of the capacitor were measured and monitored. In this paper we discuss about the design, development, implementation, performance and characteristics of the energy harvesting module.

  9. Hybridized electromagnetic-triboelectric nanogenerator for scavenging biomechanical energy for sustainably powering wearable electronics.

    Science.gov (United States)

    Zhang, Kewei; Wang, Xue; Yang, Ya; Wang, Zhong Lin

    2015-01-01

    We report a hybridized electromagnetic-triboelectric nanogenerator for highly efficient scavenging of biomechanical energy to sustainably power wearable electronics by human walking. Based on the effective conjunction of triboelectrification and electromagnetic induction, the hybridized nanogenerator, with dimensions of 5 cm × 5 cm × 2.5 cm and a light weight of 60 g, integrates a triboelectric nanogenerator (TENG) that can deliver a peak output power of 4.9 mW under a loading resistance of 6 MΩ and an electromagnetic generator (EMG) that can deliver a peak output power of 3.5 mW under a loading resistance of 2 kΩ. The hybridized nanogenerator exhibits a good stability for the output performance and a much better charging performance than that of an individual energy-harvesting unit (TENG or EMG). Furthermore, the hybridized nanogenerator integrated in a commercial shoe has been utilized to harvest biomechanical energy induced by human walking to directly light up tens of light-emitting diodes in the shoe and sustainably power a smart pedometer for reading the data of a walking step, distance, and energy consumption. A wireless pedometer driven by the hybrid nanogenerator can work well to send the walking data to an iPhone under the distance of 25 m. This work pushes forward a significant step toward energy harvesting from human walking and its potential applications in sustainably powering wearable electronics.

  10. Harvesting Energy from CO2 Emissions

    NARCIS (Netherlands)

    Hamelers, H.V.M.; Schaetzle, O.; Paz-García, J.M.; Biesheuvel, P.M.; Buisman, C.J.N.

    2014-01-01

    When two fluids with different compositions are mixed, mixing energy is released. This holds true for both liquids and gases, though in the case of gases, no technology is yet available to harvest this energy source. Mixing the CO2 in combustion gases with air represents a source of energy with a to

  11. Electronically droplet energy harvesting using piezoelectric cantilevers

    KAUST Repository

    Al Ahmad, Mahmoud Al

    2012-01-01

    A report is presented on free falling droplet energy harvesting using piezoelectric cantilevers. The harvester incorporates a multimorph clamped-free cantilever which is composed of five layers of lead zirconate titanate piezoelectric thick films. During the impact, the droplet kinetic energy is transferred into the form of mechanical stress forcing the piezoelectric structure to vibrate. Experimental results show energy of 0.3 μJ per droplet. The scenario of moderate falling drop intensity, i.e. 230 drops per second, yields a total energy of 400 μJ. © 2012 The Institution of Engineering and Technology.

  12. Vivaldi Antenna for RF Energy Harvesting

    Directory of Open Access Journals (Sweden)

    J. Schneider

    2016-12-01

    Full Text Available Energy harvesting is a future technology for capturing ambient energy from the environment to be recycled to feed low-power devices. A planar antipodal Vivaldi antenna is presented for gathering energy from GSM, WLAN, UMTS and related applications. The designed antenna has the potential to be used in energy harvesting systems. Moreover, the antenna is suitable for UWB applications, because it operates according to FCC regulations (3.1 – 10.6 GHz. The designed antenna is printed on ARLON 600 substrate and operates in frequency band from 0.810 GHz up to more than 12 GHz. Experimental results show good conformity with simulated performance.

  13. Energy harvesting with piezoelectric and pyroelectric materials

    CERN Document Server

    Muensit, Nantakan

    2011-01-01

    The purpose of this book is to present the current state of knowledge in the field of energy harvesting using piezoelectric and pyroelectric materials. The book is addressed to students and academics engaged in research in the fields of energy harvesting, material sciences and engineering. Scientists and engineers who are working in the area of energy conservation and renewable energy resources should find it useful as well. Explanations of fundamental physical properties such as piezoelectricity and pyroelectricity are included to aid the understanding of the non-specialist. Specific technolo

  14. Flexible energy harvesting from hard piezoelectric beams

    Science.gov (United States)

    Delnavaz, Aidin; Voix, Jérémie

    2016-11-01

    This paper presents design, multiphysics finite element modeling and experimental validation of a new miniaturized PZT generator that integrates a bulk piezoelectric ceramic onto a flexible platform for energy harvesting from the human body pressing force. In spite of its flexibility, the mechanical structure of the proposed device is simple to fabricate and efficient for the energy conversion. The finite element model involves both mechanical and piezoelectric parts of the device coupled with the electrical circuit model. The energy harvester prototype was fabricated and tested under the low frequency periodic pressing force during 10 seconds. The experimental results show that several nano joules of electrical energy is stored in a capacitor that is quite significant given the size of the device. The finite element model is validated by observing a good agreement between experimental and simulation results. the validated model could be used for optimizing the device for energy harvesting from earcanal deformations.

  15. Comparison between four piezoelectric energy harvesting circuits

    Institute of Scientific and Technical Information of China (English)

    Jinhao QIU; Hao JIANG; Hongli JI; Kongjun ZHU

    2009-01-01

    This paper investigates and compares the efficiencies of four different interfaces for vibration-based energy harvesting systems. Among those four circuits, two circuits adopt the synchronous switching technique, in which the circuit is switched synchronously with the vibration. In this study, a simple source-less trigger circuit used to control the synchronized switch is proposed and two interface circuits of energy harvesting systems are designed based on the trigger circuit. To validate the effectiveness of the proposed circuits, an experimental system was established and the power harvested by those circuits from a vibration beam was measured. Experimental results show that the two new circuits can increase the harvested power by factors 2.6 and 7, respectively, without consuming extra power in the circuits.

  16. Utility Optimal Scheduling in Energy Harvesting Networks

    CERN Document Server

    Huang, Longbo

    2010-01-01

    In this paper, we show how to achieve close-to-optimal utility performance in energy harvesting networks with only finite capacity energy storage devices. In these networks, nodes are capable of harvesting energy from the environment. The amount of energy that can be harvested is time varying and evolves according to some probability law. We develop an \\emph{online} algorithm, called the Energy-limited Scheduling Algorithm (ESA), which jointly manages the energy and makes power allocation decisions for packet transmissions. ESA only has to keep track of the amount of energy left at the network nodes and \\emph{does not require any knowledge} of the harvestable energy process. We show that ESA achieves a utility that is within $O(\\epsilon)$ of the optimal, for any $\\epsilon>0$, while ensuring that the network congestion and the required capacity of the energy storage devices are \\emph{deterministically} upper bounded by bounds of size $O(1/\\epsilon)$. We then also develop the Modified-ESA algorithm (MESA) to ac...

  17. Water flow energy harvesters for autonomous flowmeters

    Science.gov (United States)

    Boisseau, Sebastien; Duret, Alexandre-Benoit; Perez, Matthias; Jallas, Emmanuel; Jallas, Eric

    2016-11-01

    This paper reports on a water flow energy harvester exploiting a horizontal axis turbine with distributed magnets of alternate polarities at the rotor periphery and air coils outside the pipe. The energy harvester operates down to 1.2L/min with an inlet section of 20mm of diameter and up to 25.2mW are provided at 20L/min in a 2.4V NiMH battery through a BQ25504 power management circuit. The pressure loss induced by the insertion of the energy harvester in the hydraulic circuit and by the extraction of energy has been limited to 0.05bars at 30L/min, corresponding to a minor loss coefficient of KEH=3.94.

  18. Energy harvesting devices, systems, and related methods

    Science.gov (United States)

    Kotter, Dale K.

    2016-10-18

    Energy harvesting devices include a substrate and a plurality of resonance elements coupled to the substrate. Each resonance element is configured to collect energy in the visible and infrared light spectra and to reradiate energy having a wavelength in the range of about 0.8 .mu.m to about 0.9 .mu.m. The resonance elements are arranged in groups of two or more resonance elements. Systems for harvesting electromagnetic radiation include a substrate, a plurality of resonance elements including a conductive material carried by the substrate, and a photovoltaic material coupled to the substrate and to at least one resonance element. The resonance elements are arranged in groups, such as in a dipole, a tripole, or a bowtie configuration. Methods for forming an energy harvesting device include forming groups of two or more discrete resonance elements in a substrate and coupling a photovoltaic material to the groups of discrete resonance elements.

  19. A novel bistable energy harvesting concept

    Science.gov (United States)

    Scarselli, G.; Nicassio, F.; Pinto, F.; Ciampa, F.; Iervolino, O.; Meo, M.

    2016-05-01

    Bistable energy harvesting has become a major field of research due to some unique features for converting mechanical energy into electrical power. When properly loaded, bistable structures snap-through from one stable configuration to another, causing large strains and consequently power generation. Moreover, bistable structures can harvest energy across a broad-frequency bandwidth due to their nonlinear characteristics. Despite the fact that snap-through may be triggered regardless of the form or frequency of exciting vibration, the external force must reach a specific snap-through activation threshold value to trigger the transition from one stable state to another. This aspect is a limiting factor for realistic vibration energy harvesting application with bistable devices. This paper presents a novel power harvesting concept for bistable composites based on a ‘lever effect’ aimed at minimising the activation force to cause the snap through by choosing properly the bistable structures’ constraints. The concept was demonstrated with the help of numerical simulation and experimental testing. The results showed that the actuation force is one order of magnitude smaller (3%-6%) than the activation force of conventionally constrained bistable devices. In addition, it was shown that the output voltage was higher than the conventional configuration, leading to a significant increase in power generation. This novel concept could lead to a new generation of more efficient bistable energy harvesters for realistic vibration environments.

  20. Wind-driven pyroelectric energy harvesting device

    Science.gov (United States)

    Xie, Mengying; Zabek, Daniel; Bowen, Chris; Abdelmageed, Mostafa; Arafa, Mustafa

    2016-12-01

    Pyroelectric materials have recently received attention for harvesting waste heat owing to their potential to convert temperature fluctuations into useful electrical energy. One of the main challenges in designing pyroelectric energy harvesters is to provide a means to induce a temporal heat variation in a pyroelectric material autonomously from a steady heat source. To address this issue, we propose a new form of wind-driven pyroelectric energy harvester, in which a propeller is set in rotational motion by an incoming wind stream. The speed of the propeller’s shaft is reduced by a gearbox to drive a slider-crank mechanism, in which a pyroelectric material is placed on the slider. Thermal cycling is obtained as the reciprocating slider moves the pyroelectric material across alternative hot and cold zones created by a stationary heat lamp and ambient temperature, respectively. The open-circuit voltage and closed-circuit current are investigated in the time domain at various wind speeds. The device was experimentally tested under wind speeds ranging from 1.1 to 1.6 m s-1 and charged an external 100 nF capacitor through a signal conditioning circuit to demonstrate its effectiveness for energy harvesting. Unlike conventional wind turbines, the energy harvested by the pyroelectric material is decoupled from the wind flow and no mechanical power is drawn from the transmission; hence the system can operate at low wind speeds (<2 m s-1).

  1. Energy Harvesting from Energetic Porous Silicon

    Science.gov (United States)

    2016-07-01

    ARL-TR-7719 ● JULY 2016 US Army Research Laboratory Energy Harvesting from Energetic Porous Silicon by Louis B Levine, Matthew...it is no longer needed. Do not return it to the originator. ARL-TR-7719 ● JULY 2016 US Army Research Laboratory Energy ...

  2. Wireless Information Transfer with Opportunistic Energy Harvesting

    CERN Document Server

    Liu, Liang; Chua, Kee-Chaing

    2012-01-01

    Energy harvesting is a promising solution to prolong the operation of energy-constrained wireless networks. In particular, scavenging energy from ambient radio signals, namely wireless energy harvesting (WEH), has recently drawn significant attention. In this paper, we consider a point-to-point wireless link over the flat-fading channel subject to the time-varying co-channel interference. It is assumed that the receiver has no fixed power supplies and thus needs to replenish energy via WEH from the unintended interference and/or the intended signal sent by the transmitter. We further assume a single-antenna receiver that can only decode information or harvest energy at any given time due to the practical circuit limitation. As a result, it is important to investigate when the receiver should switch between the two modes of information decoding (ID) and energy harvesting (EH), based on the instantaneous channel and interference conditions. In this paper, we derive the optimal mode switching rule at the receive...

  3. Harvesting energy from airflow with a michromachined piezoelectric harvester inside a Helmholtz resonator

    NARCIS (Netherlands)

    Matova, S.P.; Elfrink, R.; Vullers, R.J.M.; Schaijk, R. van

    2011-01-01

    In this paper we report an airflow energy harvester that combines a piezoelectric energy harvester with a Helmholtz resonator. The resonator converts airflow energy to air oscillations which in turn are converted into electrical energy by a piezoelectric harvester. Two Helmholtz resonators with adju

  4. Harvesting bone graft from the olecranon: a quantitative and biomechanical comparison of proximal and dorsal cortical windows.

    Science.gov (United States)

    Anderson, Matthew C; Chong, Alexander C M; Lucas, George L; Czuwala, Peter J; Wooley, Paul H

    2014-07-01

    We conducted a study to compare 2 techniques of harvesting ulna bone graft from the olecranon, one using a proximal cortical window (PCW), the other using a dorsal cortical window (DCW), in terms of cancellous bone graft quantity and ulna fracture strength after graft harvest. Cancellous bone was harvested from 8 pairs of embalmed cadaver proximal ulna. Each side of a matched pair was randomly assigned to graft harvest using either a PCW or a DCW approach. Packed bone volume (PBV) was determined by placing the harvested bone into a 3-mL syringe and compacting it with a quasi-static 25-N load. Biomechanical cantilever bending was performed on each elbow to determine load at failure (LF). Paired Student t tests were used to compare PBV and LF between the experimental and control groups. The graft PBV obtained from the matched-pair specimens was not statistically different between the PCW and DCW approaches. Ulnas subjected to proximal bone harvest exhibited higher LF than ulnas subjected to dorsal bone harvest, though the difference was not statistically significant. Compared with bone graft harvest using the traditional DCW approach, harvest using a PCW approach provides similar cancellous graft amounts and exhibits similar fracture resistance.

  5. Energy Harvesting with Coupled Magnetorestrictive Resonators

    Science.gov (United States)

    2013-09-01

    energy harvesting with coupled resonators while using magnetostrictive material called Galfenol. Galfenol is an alloy iron with an approximate...follows. First we introduce the model of the transducer with Galfenol as the magnetostrictive material. Here, we discuss the model parameters derived...v  1. INTRODUCTION

  6. Vibration energy harvesting for unmanned aerial vehicles

    Science.gov (United States)

    Anton, Steven R.; Inman, Daniel J.

    2008-03-01

    Unmanned aerial vehicles (UAVs) are a critical component of many military operations. Over the last few decades, the evolution of UAVs has given rise to increasingly smaller aircraft. Along with the development of smaller UAVs, termed mini UAVs, has come issues involving the endurance of the aircraft. Endurance in mini UAVs is problematic because of the limited size of the fuel systems that can be incorporated into the aircraft. A large portion of the total mass of many electric powered mini UAVs, for example, is the rechargeable battery power source. Energy harvesting is an attractive technology for mini UAVs because it offers the potential to increase their endurance without adding significant mass or the need to increase the size of the fuel system. This paper investigates the possibility of harvesting vibration and solar energy in a mini UAV. Experimentation has been carried out on a remote controlled (RC) glider aircraft with a 1.8 m wing span. This aircraft was chosen to replicate the current electric mini UAVs used by the military today. The RC glider was modified to include two piezoelectric patches placed at the roots of the wings and a cantilevered piezoelectric beam installed in the fuselage to harvest energy from wing vibrations and rigid body motions of the aircraft, as well as two thin film photovoltaic panels attached to the top of the wings to harvest energy from sunlight. Flight testing has been performed and the power output of the piezoelectric and photovoltaic devices has been examined.

  7. Energy harvesting autonomous sensor systems design, analysis, and practical implementation

    CERN Document Server

    Tan, Yen Kheng

    2013-01-01

    This book is the considered the first to describe sensor-oriented energy harvesting issues. Its content is derived from the author's research on the development of a truly self-autonomous and sustainable energy harvesting wireless sensor network (EH-WSN). This network harvests energy from a variety of ambient energy sources and converts it into electrical energy to power batteries. The book discusses various types of energy harvesting (EH) systems and their respective main components.

  8. Tree-inspired piezoelectric energy harvesting

    Science.gov (United States)

    Hobbs, William B.; Hu, David L.

    2012-01-01

    We design and test micro-watt energy-harvesters inspired by tree trunks swaying in the wind. A uniform flow vibrates a linear array of four cylinders affixed to piezoelectric energy transducers. Particular attention is paid to measuring the energy generated as a function of cylinder spacing, flow speed, and relative position of the cylinder within the array. Peak power is generated using cylinder center-to-center spacings of 3.3 diameters and flow speeds in which the vortex shedding frequency is 1.6 times the natural frequency of the cylinders. Using these flow speeds and spacings, the power generated by downstream cylinders can exceed that of leading cylinders by more than an order of magnitude. We visualize the flow in this system by studying the behavior of a dynamically matched flowing soap film with imbedded styrofoam disks. Our qualitative visualizations suggest that peak energy harvesting occurs under conditions in which vortices have fully detached from the leading cylinder.

  9. Triboelectret-based aeroelastic flutter energy harvesters

    Science.gov (United States)

    Perez, Matthias; Boisseau, Sebastien; Geisler, Matthias; Despesse, Ghislain; Reboud, Jean Luc

    2016-11-01

    This paper highlights some experimental results on several electrostatic membranes tested in a wind tunnel between 0 and 20m.s-1 for airflow energy harvesting. The main idea is to use the aeroelastic behavior of thin flexible films to induce simultaneously the capacitance variations and the polarization required by the triboelectric/electrostatic conversion. This technology provides thin and flexible devices and avoids the issue of electrets discharge. Our prototypes (Bluetooth Low Energy) with reception on a smartphone.

  10. Pyroelectric Harvesters for Generating Cyclic Energy

    Directory of Open Access Journals (Sweden)

    Chun-Ching Hsiao

    2015-04-01

    Full Text Available Pyroelectric energy conversion is a novel energy process which directly transforms waste heat energy from cyclic heating into electricity via the pyroelectric effect. Application of a periodic temperature profile to pyroelectric cells is necessary to achieve temperature variation rates for generating an electrical output. The critical consideration in the periodic temperature profile is the frequency or work cycle which is related to the properties and dimensions of the air layer; radiation power and material properties, as well as the dimensions and structure of the pyroelectric cells. This article aims to optimize pyroelectric harvesters by matching all these requirements. The optimal induced charge per period increases about 157% and the efficient period band decreases about 77%, when the thickness of the PZT cell decreases from 200 μm to 50 μm, about a 75% reduction. Moreover, when using the thinner PZT cell for harvesting the pyroelectric energy it is not easy to focus on a narrow band with the efficient period. However, the optimal output voltage and stored energy per period decrease about 50% and 74%, respectively, because the electrical capacitance of the 50 μm thick pyroelectric cell is about four times greater than that of the 200 μm thick pyroelectric cell. In addition, an experiment is used to verify that the work cycle to be able to critically affect the efficiency of PZT pyroelectric harvesters. Periods in the range between 3.6 s and 12.2 s are useful for harvesting thermal cyclic energy by pyroelectricity. The optimal frequency or work cycle can be applied in the design of a rotating shutter in order to control the heated and unheated periods of the pyroelectric cells to further enhance the amount of stored energy.

  11. Opportunities for energy harvesting in automobile factories

    Science.gov (United States)

    Adegoke, E. I.; Edwards, R. M.; Whittow, Will; Bindel, Axel; Peca, Marco

    2016-04-01

    This paper investigates the opportunities of deploying distributed sensors within the manufacturing environment of a large scale automobile plant using energy harvesting techniques. Measurements were taken in three domains at the plant in order to characterize ambient energy. Due to the location of the plant, the RF power density for radio access technologies present varied between -127 dBm/cm2 and -113 dBm/cm2. The maximum temperature difference measured within accessible distance from machine parts on the production lines surveyed was 10°C. Indoor lighting was dominant at the plant via fluorescent tubes, with average irradiance of 1 W/m2. The results obtained from this measurement campaign showed that indoor lighting was the most suitable ambient source for energy harvesting.

  12. Vibration energy harvesting with polyphase AC transducers

    Science.gov (United States)

    McCullagh, James J.; Scruggs, Jeffrey T.; Asai, Takehiko

    2016-04-01

    Three-phase transduction affords certain advantages in the efficient electromechanical conversion of energy, especially at higher power scales. This paper considers the use of a three-phase electric machine for harvesting energy from vibrations. We consider the use of vector control techniques, which are common in the area of industrial electronics, for optimizing the feedback loops in a stochastically-excited energy harvesting system. To do this, we decompose the problem into two separate feedback loops for direct and quadrature current components, and illustrate how each might be separately optimized to maximize power output. In a simple analytical example, we illustrate how these techniques might be used to gain insight into the tradeoffs in the design of the electronic hardware and the choice of bus voltage.

  13. Energy Harvesting From Low Frequency Applications Using Piezoelectric Materials

    Energy Technology Data Exchange (ETDEWEB)

    Li, Huidong; Tian, Chuan; Deng, Zhiqun

    2014-11-06

    This paper reviewed the state of research on piezoelectric energy harvesters. Various types of harvester configurations, piezoelectric materials, and techniques used to improve the mechanical-to-electrical energy conversion efficiency were discussed. Most of the piezoelectric energy harvesters studied today have focused on scavenging mechanical energy from vibration sources due to their abundance in both natural and industrial environments. Cantilever beams have been the most studied structure for piezoelectric energy harvester to date because of the high responsiveness to small vibrations.

  14. Review of Energy Harvesters Utilizing Bridge Vibrations

    Directory of Open Access Journals (Sweden)

    Farid Ullah Khan

    2016-01-01

    Full Text Available For health monitoring of bridges, wireless acceleration sensor nodes (WASNs are normally used. In bridge environment, several forms of energy are available for operating WASNs that include wind, solar, acoustic, and vibration energy. However, only bridge vibration has the tendency to be utilized for embedded WASNs application in bridge structures. This paper reports on the recent advancements in the area of vibration energy harvesters (VEHs utilizing bridge oscillations. The bridge vibration is narrowband (1 to 40 Hz with low acceleration levels (0.01 to 3.8 g. For utilization of bridge vibration, electromagnetic based vibration energy harvesters (EM-VEHs and piezoelectric based vibration energy harvesters (PE-VEHs have been developed. The power generation of the reported EM-VEHs is in the range from 0.7 to 1450000 μW. However, the power production by the developed PE-VEHs ranges from 0.6 to 7700 μW. The overall size of most of the bridge VEHs is quite comparable and is in mesoscale. The resonant frequencies of EM-VEHs are on the lower side (0.13 to 27 Hz in comparison to PE-VEHs (1 to 120 Hz. The power densities reported for these bridge VEHs range from 0.01 to 9539.5 μW/cm3 and are quite enough to operate most of the commercial WASNs.

  15. Performance Limits of Communication with Energy Harvesting

    KAUST Repository

    Znaidi, Mohamed Ridha

    2016-04-01

    In energy harvesting communications, the transmitters have to adapt transmission to the availability of energy harvested during communication. The performance of the transmission depends on the channel conditions which vary randomly due to mobility and environmental changes. During this work, we consider the problem of power allocation taking into account the energy arrivals over time and the quality of channel state information (CSI) available at the transmitter, in order to maximize the throughput. Differently from previous work, the CSI at the transmitter is not perfect and may include estimation errors. We solve this problem with respect to the energy harvesting constraints. Assuming a perfect knowledge of the CSI at the receiver, we determine the optimal power policy for different models of the energy arrival process (offline and online model). Indeed, we obtain the power allocation scheme when the transmitter has either perfect CSI or no CSI. We also investigate of utmost interest the case of fading channels with imperfect CSI. Moreover, a study of the asymptotic behavior of the communication system is proposed. Specifically, we analyze of the average throughput in a system where the average recharge rate goes asymptotically to zero and when it is very high.

  16. Two degrees of freedom piezoelectric vibration energy harvester

    Science.gov (United States)

    Wang, Wei; Liu, Shengsheng; Cao, Junyi; Zhou, Shengxi; Lin, Jing

    2016-04-01

    Recently, vibration energy harvesting from surrounding environments to power wearable devices and wireless sensors in structure health monitoring has received considerable interest. Piezoelectric conversion mechanism has been employed to develop many successful energy harvesting devices due to its simple structure, long life span, high harvesting efficiency and so on. However, there are many difficulties of microscale cantilever configurations in energy harvesting from low frequency ambient. In order to improve the adaptability of energy harvesting from ambient vibrations, a two degrees of freedom (2-DOF) magnetic-coupled piezoelectric energy harvester is proposed in this paper. The electromechanical governing models of the cantilever and clamped hybrid energy harvester are derived to describe the dynamic characteristics for 2-DOF magnetic-coupled piezoelectric vibration energy harvester. Numerical simulations based on Matlab and ANSYS software show that the proposed magnetically coupled energy harvester can enhance the effective operating frequency bandwidth and increase the energy density. The experimental voltage responses of 2-DOF harvester under different structure parameters are acquired to demonstrate the effectiveness of the lumped parameter model for low frequency excitations. Moreover, the proposed energy harvester can enhance the energy harvesting performance over a wider bandwidth of low frequencies and has a great potential for broadband vibration energy harvesting.

  17. Recent Progress on PZT Based Piezoelectric Energy Harvesting Technologies

    OpenAIRE

    Min-Gyu Kang; Woo-Suk Jung; Chong-Yun Kang; Seok-Jin Yoon

    2016-01-01

    Energy harvesting is the most effective way to respond to the energy shortage and to produce sustainable power sources from the surrounding environment. The energy harvesting technology enables scavenging electrical energy from wasted energy sources, which always exist everywhere, such as in heat, fluids, vibrations, etc. In particular, piezoelectric energy harvesting, which uses a direct energy conversion from vibrations and mechanical deformation to the electrical energy, is a promising tec...

  18. Recent Advancements in Nanogenerators for Energy Harvesting.

    Science.gov (United States)

    Hu, Fei; Cai, Qian; Liao, Fan; Shao, Mingwang; Lee, Shuit-Tong

    2015-11-11

    Nanomaterial-based generators are a highly promising power supply for micro/nanoscale devices, capable of directly harvesting energy from ambient sources without the need for batteries. These generators have been designed within four main types: piezoelectric, triboelectric, thermoelectric, and electret effects, and consist of ZnO-based, silicon-based, ferroelectric-material-based, polymer-based, and graphene-based examples. The representative achievements, current challenges, and future prospects of these nanogenerators are discussed.

  19. MEMS-Based Waste Vibrational Energy Harvesters

    Science.gov (United States)

    2013-06-01

    7 1. Lead Zirconium Titanate (PZT) .........................................................7 2. Aluminum ...cathode AC (40 kHz) [18] 3. PADMETAL, a metal stack of 20 nm chrome and 1000 nm aluminum , oxide is deposited and etched, as shown in Figure 25f,g...final piezoelectric energy harvester after fabrication. AlN is in blue, Si is grey and buried oxide from the SOI wafer is green

  20. Energy harvesting with coupled magnetostrictive resonators

    Science.gov (United States)

    Naik, Suketu; Phipps, Alex; In, Visarath; Cavaroc, Peyton; Matus-Vargas, Antonio; Palacios, Antonio; Gonzalez-Hernandez, H. G.

    2014-03-01

    We report the investigation of an energy harvesting system composed of coupled resonators with the magnetostrictive material Galfenol (FeGa). A coupled system of meso-scale (1-10 cm) cantilever beams for harvesting vibration energy is described for powering and aiding the performance of low-power wireless sensor nodes. Galfenol is chosen in this work for its durability, compared to the brittleness often encountered with piezoelectric materials, and high magnetomechanical coupling. A lumped model, which captures both the mechanical and electrical behavior of the individual transducers, is first developed. The values of the lumped element parameters are then derived empirically from fabricated beams in order to compare the model to experimental measurements. The governing equations of the coupled system lead to a system of differential equations with all-to-all coupling between transducers. An analysis of the system equations reveals different patterns of collective oscillations. Among the many different patterns, a synchronous state appears to yield the maximum energy that can be harvested by the system. Experiments on coupled system shows that the coupled system exhibits synchronization and an increment in the output power. Discussion of the required power converters is also included.

  1. Optimal Energy Allocation for Wireless Communications with Energy Harvesting Constraints

    CERN Document Server

    Ho, Chin Keong

    2011-01-01

    We consider the use of energy harvesters, in place of conventional batteries with fixed energy storage, for point-to-point wireless communications. In addition to the challenge of transmitting in a channel with time selective fading, energy harvesters provide a perpetual but unreliable energy source. In this paper, we consider the problem of energy allocation over a finite horizon, taking into account channel conditions and energy sources that are time varying, so as to maximize the throughput. Two types of side information (SI) on the channel conditions and harvested energy are assumed to be available: causal SI (of the past and present slots) and full SI (of the past, present and future slots). We obtain structural results for the optimal energy allocation, via the use of dynamic programming and convex optimization techniques. In particular, if unlimited energy can be stored in the battery with harvested energy and full SI is available, we prove the optimality of a water-filling energy allocation solution w...

  2. Characterization of Energy Availability in RF Energy Harvesting Networks

    Directory of Open Access Journals (Sweden)

    Daniela Oliveira

    2016-01-01

    Full Text Available The multiple nodes forming a Radio Frequency (RF Energy Harvesting Network (RF-EHN have the capability of converting received electromagnetic RF signals in energy that can be used to power a network device (the energy harvester. Traditionally the RF signals are provided by high power transmitters (e.g., base stations operating in the neighborhood of the harvesters. Admitting that the transmitters are spatially distributed according to a spatial Poisson process, we start by characterizing the distribution of the RF power received by an energy harvester node. Considering Gamma shadowing and Rayleigh fading, we show that the received RF power can be approximated by the sum of multiple Gamma distributions with different scale and shape parameters. Using the distribution of the received RF power, we derive the probability of a node having enough energy to transmit a packet after a given amount of charging time. The RF power distribution and the probability of a harvester having enough energy to transmit a packet are validated through simulation. The numerical results obtained with the proposed analysis are close to the ones obtained through simulation, which confirms the accuracy of the proposed analysis.

  3. Energy harvesting with Di-Electro Active Polymers

    DEFF Research Database (Denmark)

    Due, Jens; Munk-Nielsen, Stig; Nielsen, Rasmus Ørndrup

    2010-01-01

    This article presents a way of using Di-Electro Active Polymers (D-EAPs) for harvesting mechanical energy sources. The article describes the basics of energy harvesting with D-EAPs, and an electrical model of a D-EAP is suggested. This leads to a converter design which is able to extract...... the electrical energy harvested by the D-EAP. This converter is simulated and realized. Through experimental results both the model of the DEAP and the converter are verified. It is found that it is possible to harvest energy with a D-EAP and build a converter that can extract the harvested energy....

  4. Light harvesting for quantum solar energy conversion

    Science.gov (United States)

    Markvart, Tomas

    2000-05-01

    Despite wide structural and functional differences, the laws that govern quantum solar energy conversion to chemical energy or electricity share many similarities. In the photosynthetic membrane, in common with semiconductor solar cells, the conversion process proceeds from the creation of electron-hole pairs by a photon of light, followed by charge separation to produce the required high-energy product. In many cases, however, mechanisms are needed to enhance the optical absorption cross-section and extend the spectral range of operation. A common way of achieving this is by light harvesting: light absorption by a specialised unit which transfers the energy to the conversion apparatus. This paper considers two examples of light harvesting - semiconductor solar cells and the photosynthetic apparatus - to illustrate the basic operation and principles that apply. The existence of a light harvesting unit in photosynthesis has been known since the early 1930's but details of the process - relating, in particular, to the relationship between the structure and spectral properties - are still being unravelled. The excitation energy carriers are excitons but the precise nature of the transport - via the solid state Frenkel-Peierls variety or by Förster's resonant energy transfer - is still subject to debate. In semiconductor solar cells, the energy of the absorbed photon is collected by minority carriers but the broad principles remain the same. In both cases it is shown that the rate of energy conversion is described by a law which parallels the Shockley's solar cell equation, and the light harvesting energy collection is subject to reciprocity relations which resemble Onsager's reciprocity relations between coefficients which couple appropriate forces and flows in non-equilibrium thermodynamics. Differences in the basic atomic make-up in the two systems lead to different energy transport equations. In both cases, however, similar mathematical techniques based on Green

  5. Power management for energy harvesting wireless sensors

    Science.gov (United States)

    Arms, S. W.; Townsend, C. P.; Churchill, D. L.; Galbreath, J. H.; Mundell, S. W.

    2005-05-01

    The objective of this work was to demonstrate smart wireless sensing nodes capable of operation at extremely low power levels. These systems were designed to be compatible with energy harvesting systems using piezoelectric materials and/or solar cells. The wireless sensing nodes included a microprocessor, on-board memory, sensing means (1000 ohm foil strain gauge), sensor signal conditioning, 2.4 GHz IEEE 802.15.4 radio transceiver, and rechargeable battery. Extremely low power consumption sleep currents combined with periodic, timed wake-up was used to minimize the average power consumption. Furthermore, we deployed pulsed sensor excitation and microprocessor power control of the signal conditioning elements to minimize the sensors" average contribution to power draw. By sleeping in between samples, we were able to demonstrate extremely low average power consumption. At 10 Hz, current consumption was 300 microamps at 3 VDC (900 microwatts); at 5 Hz: 400 microwatts, at 1 Hz: 90 microwatts. When the RF stage was not used, but data were logged to memory, consumption was further reduced. Piezoelectric strain energy harvesting systems delivered ~2000 microwatts under low level vibration conditions. Output power levels were also measured from two miniature solar cells; which provided a wide range of output power (~100 to 1400 microwatts), depending on the light type & distance from the source. In summary, system power consumption may be reduced by: 1) removing the load from the energy harvesting & storage elements while charging, 2) by using sleep modes in between samples, 3) pulsing excitation to the sensing and signal conditioning elements in between samples, and 4) by recording and/or averaging, rather than frequently transmitting, sensor data.

  6. Thermoelectric energy harvesting with quantum dots.

    Science.gov (United States)

    Sothmann, Björn; Sánchez, Rafael; Jordan, Andrew N

    2015-01-21

    We review recent theoretical work on thermoelectric energy harvesting in multi-terminal quantum-dot setups. We first discuss several examples of nanoscale heat engines based on Coulomb-coupled conductors. In particular, we focus on quantum dots in the Coulomb-blockade regime, chaotic cavities and resonant tunneling through quantum dots and wells. We then turn toward quantum-dot heat engines that are driven by bosonic degrees of freedom such as phonons, magnons and microwave photons. These systems provide interesting connections to spin caloritronics and circuit quantum electrodynamics.

  7. Electrochemical systems configured to harvest heat energy

    Science.gov (United States)

    Lee, Seok Woo; Yang, Yuan; Ghasemi, Hadi; Chen, Gang; Cui, Yi

    2017-01-31

    Electrochemical systems for harvesting heat energy, and associated electrochemical cells and methods, are generally described. The electrochemical cells can be configured, in certain cases, such that at least a portion of the regeneration of the first electrochemically active material is driven by a change in temperature of the electrochemical cell. The electrochemical cells can be configured to include a first electrochemically active material and a second electrochemically active material, and, in some cases, the absolute value of the difference between the first thermogalvanic coefficient of the first electrochemically active material and the second thermogalvanic coefficient of the second electrochemically active material is at least about 0.5 millivolts/Kelvin.

  8. System for harvesting water wave energy

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Zhong Lin; Su, Yanjie; Zhu, Guang; Chen, Jun

    2016-07-19

    A generator for harvesting energy from water in motion includes a sheet of a hydrophobic material, having a first side and an opposite second side, that is triboelectrically more negative than water. A first electrode sheet is disposed on the second side of the sheet of a hydrophobic material. A second electrode sheet is disposed on the second side of the sheet of a hydrophobic material and is spaced apart from the first electrode sheet. Movement of the water across the first side induces an electrical potential imbalance between the first electrode sheet and the second electrode sheet.

  9. Flow Energy Piezoelectric Bimorph Nozzle Harvester

    Science.gov (United States)

    Sherrit, Stewart; Lee, Hyeong Jae; Kim, Namhyo; Sun, Kai; Corbett, Gary; Walkemeyer, Phillip; Hasenoehrl, Jennifer; Hall, Jeffery L.; Colonius, Tim; Tosi, Luis Phillipe; Arrazola, Alvaro

    2014-01-01

    There is a need for a long-life power generation scheme that could be used downhole in an oil well to produce 1 Watt average power. There are a variety of existing or proposed energy harvesting schemes that could be used in this environment but each of these has its own limitations. The vibrating piezoelectric structure is in principle capable of operating for very long lifetimes (decades) thereby possibly overcoming a principle limitation of existing technology based on rotating turbo-machinery. In order to determine the feasibility of using piezoelectrics to produce suitable flow energy harvesting, we surveyed experimentally a variety of nozzle configurations that could be used to excite a vibrating piezoelectric structure in such a way as to enable conversion of flow energy into useful amounts of electrical power. These included reed structures, spring mass-structures, drag and lift bluff bodies and a variety of nozzles with varying flow profiles. Although not an exhaustive survey we identified a spline nozzle/piezoelectric bimorph system that experimentally produced up to 3.4 mW per bimorph. This paper will discuss these results and present our initial analyses of the device using dimensional analysis and constitutive electromechanical modeling. The analysis suggests that an order-of-magnitude improvement in power generation from the current design is possible.

  10. Frequency adjustable MEMS vibration energy harvester

    Science.gov (United States)

    Podder, P.; Constantinou, P.; Amann, A.; Roy, S.

    2016-10-01

    Ambient mechanical vibrations offer an attractive solution for powering the wireless sensor nodes of the emerging “Internet-of-Things”. However, the wide-ranging variability of the ambient vibration frequencies pose a significant challenge to the efficient transduction of vibration into usable electrical energy. This work reports the development of a MEMS electromagnetic vibration energy harvester where the resonance frequency of the oscillator can be adjusted or tuned to adapt to the ambient vibrational frequency. Micro-fabricated silicon spring and double layer planar micro-coils along with sintered NdFeB micro-magnets are used to construct the electromagnetic transduction mechanism. Furthermore, another NdFeB magnet is adjustably assembled to induce variable magnetic interaction with the transducing magnet, leading to significant change in the spring stiffness and resonance frequency. Finite element analysis and numerical simulations exhibit substantial frequency tuning range (25% of natural resonance frequency) by appropriate adjustment of the repulsive magnetic interaction between the tuning and transducing magnet pair. This demonstrated method of frequency adjustment or tuning have potential applications in other MEMS vibration energy harvesters and micromechanical oscillators.

  11. Models for 31-mode PVDF energy harvester for wearable applications.

    Science.gov (United States)

    Zhao, Jingjing; You, Zheng

    2014-01-01

    Currently, wearable electronics are increasingly widely used, leading to an increasing need of portable power supply. As a clean and renewable power source, piezoelectric energy harvester can transfer mechanical energy into electric energy directly, and the energy harvester based on polyvinylidene difluoride (PVDF) operating in 31-mode is appropriate to harvest energy from human motion. This paper established a series of theoretical models to predict the performance of 31-mode PVDF energy harvester. Among them, the energy storage one can predict the collected energy accurately during the operation of the harvester. Based on theoretical study and experiments investigation, two approaches to improve the energy harvesting performance have been found. Furthermore, experiment results demonstrate the high accuracies of the models, which are better than 95%.

  12. Photovoltaic Energy Harvester with Power Management System

    Directory of Open Access Journals (Sweden)

    M. Ferri

    2010-01-01

    Full Text Available We present a photovoltaic energy harvester, realized in 0.35-μm CMOS technology. The proposed system collects light energy from the environment, by means of 2-mm2 on-chip integrated microsolar cells, and accumulates it in an external capacitor. While the capacitor is charging, the load is disconnected. When the energy in the external capacitor is enough to operate the load for a predefined time slot, the load is connected to the capacitor by a power management circuit. The choice of the value of the capacitance determines the operating time slot for the load. The proposed solution is suitable for discrete-time-regime applications, such as sensor network nodes, or, in general, systems that require power supply periodically for short time slots. The power management circuit includes a charge pump, a comparator, a level shifter, and a linear voltage regulator. The whole system has been extensively simulated, integrated, and experimentally characterized.

  13. Electromechanical performances of different shapes of piezoelectric energy harvesters

    Energy Technology Data Exchange (ETDEWEB)

    Paquin, S.; St-Amant, Y. [Laval Univ., Quebec City, PQ (Canada). Dept. of Mechanical Engineering

    2009-07-01

    This study examined the feasibility of harvesting mechanical energy from vibrating structures using the direct piezoelectric effect of a bimorph cantilever beam with integrated piezoceramic elements. A harvester consisting of a cantilever tapered beam, two bonded piezoelectric ceramics and two masses at its end was investigated with particular reference to the effect of harvester geometry on electromechanical performance. This paper summarized the material properties of each element and presented numerical simulations to demonstrate the increase in performances when using a tapered beam harvester instead of constant cross section harvester. Three case studies were presented, including a standard rectangular harvester, an equivalent mass/stiffness tapered beam harvester and an equivalent maximal strain tapered beam harvester. They all had a first short circuit natural frequency of 100 Hz. In order to evaluate model quality and the results accuracy, the harvester structure was modeled using finite element with NxNastran 5. The study showed that the efficiency of a cantilever beam vibration energy harvester can be increased by using a variable thickness. A semianalytical model that takes both the dynamic and the electromechanical behaviour of the harvester into account showed that the energy harvested can be increased by 69 per cent when the thickness of the beam was varied. Varying the thickness of the beam also results in more uniform strain distribution, thereby increasing the amount of energy that can be harvested. 7 refs., 2 tabs., 6 figs.

  14. Task Scheduling in Energy Harvesting Real-time Embedded Systems

    OpenAIRE

    Chetto, Maryline

    2012-01-01

    International audience; Harvesting energy from the environment is very desirable for many emerging applications that use embedded devices. Energy harvesting also known as energy scavenging enables us to guarantee quasi-perpetual system operation for wireless sensors, medical implants, etc. without requiring human intervention which is normally necessary for recharging batteries in classical battery-operated systems. Nevertheless, energy harvesting calls for solving numerous technological prob...

  15. Potential Ambient Energy-Harvesting Sources and Techniques

    Science.gov (United States)

    Yildiz, Faruk

    2009-01-01

    Ambient energy harvesting is also known as energy scavenging or power harvesting, and it is the process where energy is obtained from the environment. A variety of techniques are available for energy scavenging, including solar and wind powers, ocean waves, piezoelectricity, thermoelectricity, and physical motions. For example, some systems…

  16. Harvesting Energy from Vibrations of the Underlying Structure

    DEFF Research Database (Denmark)

    Han, Bo; Vssilaras, S; Papadias, C.B.

    2013-01-01

    on the type of power supply. No matter how energy efficient the operation of a battery operated sensor is, the energy of the battery will be exhausted at some point. In order to achieve a virtually unlimited lifetime, the sensor node should be able to recharge its battery in an easy way. Energy harvesting...... emerges as a technique that can harvest energy from the surrounding environment. Among all possible energy harvesting solutions, kinetic energy harvesting seems to be the most convenient, especially for sensors placed on structures that experience regular vibrations. Such micro-vibrations can be harmful...... to the long-term structural health of a building or bridge, but at the same time they can be exploited as a power source to power the wireless sensors that are monitoring this structural health. This paper presents a new energy harvesting method based on a vibration driven electromagnetic harvester. By using...

  17. Energy Harvesting Using Screen Printed PZT on Silicon

    DEFF Research Database (Denmark)

    Lei, Anders

    The objective of the work presented in this Ph.D. thesis is to design and fabricate a miniaturised vibration energy harvester based on screen printed PZT thick film and silicon MEMS processing technology. The vision of the vibration energy harvester is to eliminate the need for batteries...... by harvesting energy on-site from a vibration source, thereby enabling fully autonomous wireless sensor systems. The vibration harvester is a resonator consisting of a silicon support cantilever with screen printed PZT thick film on top and with an integrated proof mass at the cantilever tip. To achieve...... acceleration of 0.5g at 511 Hz. The best performing devices under similar conditions produced 44.9 µW at 543 Hz. Compared to other state of the art miniaturised vibration energy harvesters, the normalised power density for the harvesters fabricated in this work is 3.5 times higher than the next best harvester....

  18. Development of energy forest harvester. Utveckling av energiskogsskoerdare

    Energy Technology Data Exchange (ETDEWEB)

    Albertsson, N.; Nilsson, K.

    1988-01-01

    The proposal is based on a system made of a tractor with detachable harvesting equipment. The material is left on the field to be collected later. The specifications are adapted to the current situation. New harvesting methods are suggested. Harvesting and management cost of energy forestry are presented. (G.B.).

  19. Pyroelectric Energy Harvesting: With Thermodynamic-Based Cycles

    Directory of Open Access Journals (Sweden)

    Saber Mohammadi

    2012-01-01

    Full Text Available This work deals with energy harvesting from temperature variations using ferroelectric materials as a microgenerator. The previous researches show that direct pyroelectric energy harvesting is not effective, whereas thermodynamic-based cycles give higher energy. Also, at different temperatures some thermodynamic cycles exhibit different behaviours. In this paper pyroelectric energy harvesting using Lenoir and Ericsson thermodynamic cycles has been studied numerically and the two cycles were compared with each other. The material used is the PMN-25 PT single crystal that is a very interesting material in the framework of energy harvesting and sensor applications.

  20. Optimal Transmission Policies for Energy Harvesting Two-hop Networks

    CERN Document Server

    Orhan, Oner

    2012-01-01

    In this paper, a two-hop communication system with energy harvesting nodes is considered. Unlike battery powered wireless nodes, both the source and the relay are able to harvest energy from environment during communication, therefore, both data and energy causality over the two hops need to be considered. Assuming both nodes know the harvested energies in advance, properties of optimal transmission policies to maximize the delivered data by a given deadline are identified. Using these properties, optimal power allocation and transmission schedule for the case in which both nodes harvest two energy packets is developed.

  1. A novel method for piezoelectric energy harvesting from keyboard

    Science.gov (United States)

    Beker, Levent; Muhtaroglu, Ali; Külah, Haluk

    2012-04-01

    This paper presents a novel method and apparatus for converting keystrokes to electrical energy using a resonant energy harvester, which can be coupled with keyboards. The state-of-the-art dome switch design is modified to excite the tip of the energy harvester beam. Piezoelectric transduction converts vibrations to electrical power. The energy harvester design is optimized to give highest voltage output under use conditions, and is fabricated. A close match is observed for the first natural frequency. When the piezoelectric energy harvester is excited at 7.62 Hz with tip excitation to emulate keyboard use, 16.95 μW of power is generated.

  2. Robust Energy Scheduling for Wireless Communication under Harvesting Uncertainty

    Directory of Open Access Journals (Sweden)

    Hua Xiao

    2012-08-01

    Full Text Available In this study, we investigate the energy scheduling problem for wireless communication with energy harvesting devices. We consider wireless transmission systems equipped with energy harvesting devices, which can provide sustainable energy to substitute traditional battery. One of challenging in the system is to efficiently schedule energy consumption to maximize the utility and to adapt to the energy harvesting process. In general, it is difficult to obtain the accurate energy harvesting model parameters. On the other hand, model errors could considerably deteriorate the performances of traditional energy management approaches. We therefore consider robust energy scheduling schemes under the model uncertainty of the energy harvesting process. The problem is formulated as a robust Markov decision process and efficiently solved by robust dynamic programming. Extensive simulation results verify our proposed approaches.

  3. Flexible Piezoelectric Energy Harvesting from Mouse Click Motions.

    Science.gov (United States)

    Cha, Youngsu; Hong, Jin; Lee, Jaemin; Park, Jung-Min; Kim, Keehoon

    2016-07-06

    In this paper, we study energy harvesting from the mouse click motions of a robot finger and a human index finger using a piezoelectric material. The feasibility of energy harvesting from mouse click motions is experimentally and theoretically assessed. The fingers wear a glove with a pocket for including the piezoelectric material. We model the energy harvesting system through the inverse kinematic framework of parallel joints in a finger and the electromechanical coupling equations of the piezoelectric material. The model is validated through energy harvesting experiments in the robot and human fingers with the systematically varying load resistance. We find that energy harvesting is maximized at the matched load resistance to the impedance of the piezoelectric material, and the harvested energy level is tens of nJ.

  4. Piezoelectric Energy Harvesting in Internal Fluid Flow

    Directory of Open Access Journals (Sweden)

    Hyeong Jae Lee

    2015-10-01

    Full Text Available We consider piezoelectric flow energy harvesting in an internal flow environment with the ultimate goal powering systems such as sensors in deep oil well applications. Fluid motion is coupled to structural vibration via a cantilever beam placed in a converging-diverging flow channel. Two designs were considered for the electromechanical coupling: first; the cantilever itself is a piezoelectric bimorph; second; the cantilever is mounted on a pair of flextensional actuators. We experimentally investigated varying the geometry of the flow passage and the flow rate. Experimental results revealed that the power generated from both designs was similar; producing as much as 20 mW at a flow rate of 20 L/min. The bimorph designs were prone to failure at the extremes of flow rates tested. Finite element analysis (FEA showed fatigue failure was imminent due to stress concentrations near the bimorph’s clamped region; and that robustness could be improved with a stepped-joint mounting design. A similar FEA model showed the flextensional-based harvester had a resonant frequency of around 375 Hz and an electromechanical coupling of 0.23 between the cantilever and flextensional actuators in a vacuum. These values; along with the power levels demonstrated; are significant steps toward building a system design that can eventually deliver power in the Watts range to devices down within a well.

  5. Harvesting dissipated energy with a mesoscopic ratchet.

    Science.gov (United States)

    Roche, B; Roulleau, P; Jullien, T; Jompol, Y; Farrer, I; Ritchie, D A; Glattli, D C

    2015-04-01

    The search for new efficient thermoelectric devices converting waste heat into electrical energy is of major importance. The physics of mesoscopic electronic transport offers the possibility to develop a new generation of nanoengines with high efficiency. Here we describe an all-electrical heat engine harvesting and converting dissipated power into an electrical current. Two capacitively coupled mesoscopic conductors realized in a two-dimensional conductor form the hot source and the cold converter of our device. In the former, controlled Joule heating generated by a voltage-biased quantum point contact results in thermal voltage fluctuations. By capacitive coupling the latter creates electric potential fluctuations in a cold chaotic cavity connected to external leads by two quantum point contacts. For unequal quantum point contact transmissions, a net electrical current is observed proportional to the heat produced.

  6. Magnetically levitated autoparametric broadband vibration energy harvesting

    Science.gov (United States)

    Kurmann, L.; Jia, Y.; Manoli, Y.; Woias, P.

    2016-11-01

    Some of the lingering challenges within the current paradigm of vibration energy harvesting (VEH) involve narrow operational frequency range and the inevitable non-resonant response from broadband noise excitations. Such VEHs are only suitable for limited applications with fixed sinusoidal vibration, and fail to capture a large spectrum of the real world vibration. Various arraying designs, frequency tuning schemes and nonlinear vibratory approaches have only yielded modest enhancements. To fundamentally address this, the paper proposes and explores the potentials in using highly nonlinear magnetic spring force to activate an autoparametric oscillator, in order to realize an inherently broadband resonant system. Analytical and numerical modelling illustrate that high spring nonlinearity derived from magnetic levitation helps to promote the 2:1 internal frequency matching required to activate parametric resonance. At the right internal parameters, the resulting system can intrinsically exhibit semi-resonant response regardless of the bandwidth of the input vibration, including broadband white noise excitation.

  7. MEMS based pyroelectric thermal energy harvester

    Energy Technology Data Exchange (ETDEWEB)

    Hunter, Scott R; Datskos, Panagiotis G

    2013-08-27

    A pyroelectric thermal energy harvesting apparatus for generating an electric current includes a cantilevered layered pyroelectric capacitor extending between a first surface and a second surface, where the first surface includes a temperature difference from the second surface. The layered pyroelectric capacitor includes a conductive, bimetal top electrode layer, an intermediate pyroelectric dielectric layer and a conductive bottom electrode layer. In addition, a pair of proof masses is affixed at a distal end of the layered pyroelectric capacitor to face the first surface and the second surface, wherein the proof masses oscillate between the first surface and the second surface such that a pyroelectric current is generated in the pyroelectric capacitor due to temperature cycling when the proof masses alternately contact the first surface and the second surface.

  8. Energy Harvesting Using PVDF Piezoelectric Nanofabric

    Science.gov (United States)

    Shafii, Chakameh Shafii

    Energy harvesting using piezoelectric nanomaterial provides an opportunity for advancement towards self-powered electronics. The fabrication complexities and limited power output of these nano/micro generators have hindered these advancements thus far. This thesis presents a fabrication technique with electrospinning using a grounded cylinder as the collector. This method addresses the difficulties with the production and scalability of the nanogenerators. The non-aligned nanofibers are woven into a textile form onto the cylindrical drum that can be easily removed. The electrical poling and mechanical stretching induced by the electric field and the drum rotation increase the concentration of the piezoelectric beta phase in the PVDF nanofabric. The nanofabric is placed between two layers of polyethylene terephthalate (PET) that have interdigitated electrodes painted on them with silver paint. Applying continuous load onto the flexible PVDF nanofabric at 35Hz produces a peak voltage of 320 mV and maximum power of 2200 pW/(cm2) .

  9. Sustainable Performance in Energy Harvesting - Wireless Sensor Networks

    DEFF Research Database (Denmark)

    Fafoutis, Xenofon; Di Mauro, Alessio; Dragoni, Nicola

    2013-01-01

    In this practical demo we illustrate the concept of "sustainable performance" in Energy-Harvesting Wireless Sensor Networks (EH-WSNs). In particular, for different classes of applications and under several energy harvesting scenarios, we show how it is possible to have sustainable performance when...... nodes in the network are powered by ambient energy....

  10. Nano/microscale pyroelectric energy harvesting: challenges and opportunities

    Directory of Open Access Journals (Sweden)

    Devashish Lingam

    2013-12-01

    Full Text Available With the ever-growing demand for renewable energy sources, energy harvesting from natural resources has gained much attention. Energy sources such as heat and mechanical motion could be easily harvested based on pyroelectric, thermoelectric, and piezoelectric effects. The energy harvested from otherwise wasted energy in the environment can be utilized in self-powered micro and nano devices, and wearable electronics, which required only µW–mW power. This article reviews pyroelectric energy harvesting with an emphasis on recent developments in pyroelectric energy harvesting and devices at micro/nanoscale. Recent developments are presented and future challenges and opportunities for more efficient materials and devices with higher energy conversion efficiency are also discussed.

  11. Enhanced PVDF film for multi energy harvesting

    Science.gov (United States)

    Karunarathna, Ranmunige Nadeeka

    PVDF is a very important piezoelectric polymer material which has a promising range of applications in a variety of fields such as acoustic sensors and transducers, electrical switches, medical instrumentation, artificial sensitive skin in robotics, automotive detection on roads, nondestructive testing, structural health monitoring and as a biocampatible material. In this research cantilever based multi energy harvester was developed to maximize the power output of PVDF sensor. Nano mixture containing ferrofluid (FF) and ZnO nano particles were used to enhance the piezoelectric output of the sensor. The samples were tested under different energy conditions to observe the behavior of nano coated PVDF film under multi energy conditions. Composition of the ZnO and FF nano particles were changed by weight, in order to achieve the optimal composition of the nano mixture. Light energy, vibration energy, combined effect of light and vibration energy, and magnetic effect were used to explore the behavior of the sensor. The sensor with 60% ZnO and 40% FF achieved a maximum power output of 10.7 microwatts when it is under the combined effect of light and vibration energy. Which is nearly 16 times more power output than PVDF sensor. When the magnetic effect is considered the sensor with 100% FF showed the highest power output of 11.2 microwatts which is nearly 17 times more power output than pure PVDF. The effective piezoelctric volume of the sensor was 0.017 cm3. In order to explore the effect of magnetic flux, cone patterns were created on the sensor by means of a external magnetic field. Stability of the cones generated on the sensor played a major role in generated power output.

  12. Pyroelectric nanogenerators for harvesting thermoelectric energy.

    Science.gov (United States)

    Yang, Ya; Guo, Wenxi; Pradel, Ken C; Zhu, Guang; Zhou, Yusheng; Zhang, Yan; Hu, Youfan; Lin, Long; Wang, Zhong Lin

    2012-06-13

    Harvesting thermoelectric energy mainly relies on the Seebeck effect that utilizes a temperature difference between two ends of the device for driving the diffusion of charge carriers. However, in an environment that the temperature is spatially uniform without a gradient, the pyroelectric effect has to be the choice, which is based on the spontaneous polarization in certain anisotropic solids due to a time-dependent temperature variation. Using this effect, we experimentally demonstrate the first application of pyroelectric ZnO nanowire arrays for converting heat energy into electricity. The coupling of the pyroelectric and semiconducting properties in ZnO creates a polarization electric field and charge separation along the ZnO nanowire as a result of the time-dependent change in temperature. The fabricated nanogenerator has a good stability, and the characteristic coefficient of heat flow conversion into electricity is estimated to be ∼0.05-0.08 Vm(2)/W. Our study has the potential of using pyroelectric nanowires to convert wasted energy into electricity for powering nanodevices.

  13. Energy harvesting using vortex-induced vibrations of tensioned cables

    CERN Document Server

    Grouthier, Clement; de Langre, Emmanuel

    2012-01-01

    The development of energy harvesting systems based on fluid/structure interactions is part of the global search for innovative tools to produce renewable energy. In this paper, the possibility to harvest energy from a flow using vortex-induced vibrations (VIV) of a tensioned flexible cable is analyzed. The fluid loading on the vibrating solid and resulting dynamics are computed using an appropriate wake-oscillator model, allowing one to perform a systematic parametric study of the efficiency. The generic case of an elastically-mounted rigid cylinder is first investigated, before considering an infinite cable with two different types of energy harvesting : a uniformly spanwise distributed harvesting and then a periodic distribution of discrete harvesting devices. The maximum harvesting efficiency is of the same order for each configuration and is always reached when the solid body and its wake are in a frequency lock-in state.

  14. Recent Progress on PZT Based Piezoelectric Energy Harvesting Technologies

    Directory of Open Access Journals (Sweden)

    Min-Gyu Kang

    2016-02-01

    Full Text Available Energy harvesting is the most effective way to respond to the energy shortage and to produce sustainable power sources from the surrounding environment. The energy harvesting technology enables scavenging electrical energy from wasted energy sources, which always exist everywhere, such as in heat, fluids, vibrations, etc. In particular, piezoelectric energy harvesting, which uses a direct energy conversion from vibrations and mechanical deformation to the electrical energy, is a promising technique to supply power sources in unattended electronic devices, wireless sensor nodes, micro-electronic devices, etc., since it has higher energy conversion efficiency and a simple structure. Up to now, various technologies, such as advanced materials, micro- and macro-mechanics, and electric circuit design, have been investigated and emerged to improve performance and conversion efficiency of the piezoelectric energy harvesters. In this paper, we focus on recent progress of piezoelectric energy harvesting technologies based on PbZrxTi1-xO3 (PZT materials, which have the most outstanding piezoelectric properties. The advanced piezoelectric energy harvesting technologies included materials, fabrications, unique designs, and properties are introduced to understand current technical levels and suggest the future directions of piezoelectric energy harvesting.

  15. Energy Harvesting and Information Transmission Protocol in Sensors Networks

    Directory of Open Access Journals (Sweden)

    Xue-Fen Zhang

    2016-01-01

    Full Text Available We focus on the design of transmission protocol for energy harvesting wireless sensors. The sensors can harvest the energy from the environment, but they cannot charge and discharge at the same time. We propose a protocol for energy harvesting and wireless transmission, which contains two steps. In the first step, the sensor harvests the energy from environment, and the energy harvesting rate is controlled by the harvested energy power of the energy saving device (ESD. In the second step, some data should be transmitted to the receiver in a certain time. Considering one slot time, the first part of the time is devoted exclusively to energy harvesting, and the remaining time of the slot is for transmitting the information data. Assume that Q bits are transmitted to the receiver within one time slot; we establish the relationship between the harvesting energy time and the transmit data time. In addition, we analyze the system outage probability performance over the Rayleigh fading channel.

  16. Flexible piezoelectric thin-film energy harvesters and nanosensors for biomedical applications.

    Science.gov (United States)

    Hwang, Geon-Tae; Byun, Myunghwan; Jeong, Chang Kyu; Lee, Keon Jae

    2015-04-02

    The use of inorganic-based flexible piezoelectric thin films for biomedical applications has been actively reported due to their advantages of highly piezoelectric, pliable, slim, lightweight, and biocompatible properties. The piezoelectric thin films on plastic substrates can convert ambient mechanical energy into electric signals, even responding to tiny movements on corrugated surfaces of internal organs and nanoscale biomechanical vibrations caused by acoustic waves. These inherent properties of flexible piezoelectric thin films enable to develop not only self-powered energy harvesters for eliminating batteries of bio-implantable medical devices but also sensitive nanosensors for in vivo diagnosis/therapy systems. This paper provides recent progresses of flexible piezoelectric thin-film harvesters and nanosensors for use in biomedical fields. First, developments of flexible piezoelectric energy-harvesting devices by using high-quality perovskite thin film and innovative flexible fabrication processes are addressed. Second, their biomedical applications are investigated, including self-powered cardiac pacemaker, acoustic nanosensor for biomimetic artificial hair cells, in vivo energy harvester driven by organ movements, and mechanical sensor for detecting nanoscale cellular deflections. At the end, future perspective of a self-powered flexible biomedical system is also briefly discussed with relation to the latest advancements of flexible electronics.

  17. Experimental evaluation of a cruciform piezoelectric energy harvester

    Science.gov (United States)

    Tsuruta, Karina M.; Rade, Domingos A.; Finzi Neto, Roberto M.; Cavalini, Aldemir A.

    2016-10-01

    This paper describes the development and experimental evaluation of a particular type of piezoelectric energy harvester, composed of four aluminum cantilever blades to which piezoelectric patches are bonded, in such way that electric energy is generated when the blades undergo bending vibrations. Concentrated masses, whose values can be varied, are attached to the tips of the blades. Due to the geometric shape of the harvester, in which the four blades are oriented forming right angles, the harvester is named cruciform. As opposed to the large majority of previous works on the subject, in which harvesters are excited at their bases by prescribed acceleration, herein the harvester is connected to a vibrating structure excited by an imbalance force. Hence, the amount of harvested energy depends upon the dynamic interaction between the harvester and the host structure. Laboratory experiments were carried-out on a prototype connected to a tridimensional truss. The experimental setup includes a force generator consisting of an imbalanced disc driven by an electrical motor whose rotation is controlled electronically, a voltage rectifier circuit, and a battery charged with the harvested energy. After characterization of the dynamic behavior of the harvester and the host structure, both numerically and experimentally, the results of experiments are presented and discussed in terms of the voltage output of the piezoelectric transducers as function of the excitation frequency and the values of the tip masses. Also, the capacity of the harvester to charge a Lithium battery is evaluated.

  18. An electromechanical model of ferroelectret for energy harvesting

    Science.gov (United States)

    Luo, Zhenhua; Zhu, Dibin; Beeby, Steve

    2016-04-01

    A ferroelectret is a cellular polymer foam that is able to convert compressive and bending forces into electrical signals, which can be used for both sensing and energy harvesting. In the past several research groups have proposed theoretical models that relate the output voltage of a ferroelectret to its mechanical deformation. This is particularly useful for sensing applications where the signal-to-noise ratio is important. However, for energy harvesting applications, a theoretical model needs to include both the voltage across a resistive load and the duration of the electrical signal as energy is an integral of power over time. In this work, we propose a theoretical model that explains the behavior of a ferroelectret when used as an energy harvester. This model can be used to predict the energy output of a ferroelectret by knowing its parameters, and therefore optimize the harvester design for specific energy harvesting application.

  19. A low frequency rotational energy harvesting system

    Science.gov (United States)

    Febbo, M.; Machado, S. P.; Ramirez, J. M.; Gatti, C. D.

    2016-11-01

    This paper presents a rotary power scavenging unit comprised of two systems of flexible beams connected by two masses which are joined by means of a spring, considering a PZT (QP16N, Midé Corporation) piezoelectric sheet mounted on one of the beams. The energy harvesting (EH) system is mounted rigidly on a rotating hub. The gravitational force on the masses causes sustained oscillatory motion in the flexible beams as long as there is rotary motion. The intention is to use the EH system in the wireless autonomous monitoring of wind turbines under different wind conditions. Specifically, the development is oriented to monitor the dynamic state of the blades of a wind generator of 30 KW which rotates between 50 and 150 rpm. The paper shows a complete set of experimental results on three devices, modifying the amount of beams in the frame supporting the system. The results show an acceptable sustained voltage generation for the expected range, in the three proposed cases. Therefore, it is possible to use this system for generating energy in a low-frequency rotating environment. As an alternative, the system can be easily adapted to include an array of piezoelectric sheets to each of the beams, to provide more power generation.

  20. Energy Harvesting From Sea Waves With Consideration of Airy and JONSWAP Theory and Optimization of Energy Harvester Parameters

    Institute of Scientific and Technical Information of China (English)

    Hadi Mirab; Reza Fathi; Vahid Jahangiri; Mir Mohammad Ettefagh; Reza Hassannejad

    2015-01-01

    One of the new methods for powering low-power electronic devices at sea is a wave energy harvesting system. In this method, piezoelectric material is employed to convert the mechanical energy of sea waves into electrical energy. The advantage of this method is based on avoiding a battery charging system. Studies have been done on energy harvesting from sea waves, however, considering energy harvesting with random JONSWAP wave theory, then determining the optimum values of energy harvested is new. This paper does that by implementing the JONSWAP wave model, calculating produced power, and realistically showing that output power is decreased in comparison with the more simple Airy wave model. In addition, parameters of the energy harvester system are optimized using a simulated annealing algorithm, yielding increased produced power.

  1. Modeling and Optimization of an Electrostatic Energy Harvesting Device

    DEFF Research Database (Denmark)

    Crovetto, Andrea; Wang, Fei; Hansen, Ole

    2014-01-01

    Modeling of energy harvesting devices is complicated by the coupling between electrical and mechanical domains. In this paper, we present a coupled electromechanical model for electret-based resonant energy harvesters where the two output pads are placed on the same device side (single...

  2. Energy harvesting for human wearable and implantable bio-sensors.

    Science.gov (United States)

    Mitcheson, Paul D

    2010-01-01

    There are clear trade-offs between functionality, battery lifetime and battery volume for wearable and implantable wireless-biosensors which energy harvesting devices may be able to overcome. Reliable energy harvesting has now become a reality for machine condition monitoring and is finding applications in chemical process plants, refineries and water treatment works. However, practical miniature devices that can harvest sufficient energy from the human body to power a wireless bio-sensor are still in their infancy. This paper reviews the options for human energy harvesting in order to determine power availability for harvester-powered body sensor networks. The main competing technologies for energy harvesting from the human body are inertial kinetic energy harvesting devices and thermoelectric devices. These devices are advantageous to some other types as they can be hermetically sealed. In this paper the fundamental limit to the power output of these devices is compared as a function of generator volume when attached to a human whilst walking and running. It is shown that the kinetic energy devices have the highest fundamental power limits in both cases. However, when a comparison is made between the devices using device effectivenesses figures from previously demonstrated prototypes presented in the literature, the thermal device is competitive with the kinetic energy harvesting device when the subject is running and achieves the highest power density when the subject is walking.

  3. A dimensionless model of impact piezoelectric energy harvesting with dissipation

    Science.gov (United States)

    Fu, Xinlei; Liao, Wei-Hsin

    2016-04-01

    Impact excitation is common in the environment. Impact piezoelectric energy harvesting could realize frequency up-conversion. However, the dissipation mechanism in impact piezoelectric energy harvesting has not been investigated so far. There is no comprehensive model to be able to analyze the impact piezoelectric energy harvesting thoroughly. This paper is aimed to develop a generalized model that considers dissipation mechanism of impact piezoelectric energy harvesting. In this electromechanical model, Hertzian contact theory and impact dissipation mechanism are identified as constitutive mechanisms. The impact force is compared and the energy distribution is analyzed so that input energy corresponds to impact dissipated energy, structural damping dissipated energy and harvested electrical energy. We then nondimensionalize the developed model and define five dimensionless parameters with attributed physical meanings, including dimensionless parameters of impact dissipation, mass ratio, structural damping, electromechanical coupling, and electrical load. We conclude it is more accurate to consider impact dissipation mechanism to predict impact force and harvested energy. The guideline for improving harvested energy based on parametric studies of dimensionless model is to increase mass ratio, to minimize structural damping, to maximize electromechanical coupling, to use optimal load resistance for impedance matching, and to choose proper impact velocity .

  4. Maximum power point tracking for optimizing energy harvesting process

    Science.gov (United States)

    Akbari, S.; Thang, P. C.; Veselov, D. S.

    2016-10-01

    There has been a growing interest in using energy harvesting techniques for powering wireless sensor networks. The reason for utilizing this technology can be explained by the sensors limited amount of operation time which results from the finite capacity of batteries and the need for having a stable power supply in some applications. Energy can be harvested from the sun, wind, vibration, heat, etc. It is reasonable to develop multisource energy harvesting platforms for increasing the amount of harvesting energy and to mitigate the issue concerning the intermittent nature of ambient sources. In the context of solar energy harvesting, it is possible to develop algorithms for finding the optimal operation point of solar panels at which maximum power is generated. These algorithms are known as maximum power point tracking techniques. In this article, we review the concept of maximum power point tracking and provide an overview of the research conducted in this area for wireless sensor networks applications.

  5. Power conditioning for low-voltage piezoelectric stack energy harvesters

    Science.gov (United States)

    Skow, E.; Leadenham, S.; Cunefare, K. A.; Erturk, A.

    2016-04-01

    Low-power vibration and acoustic energy harvesting scenarios typically require a storage component to be charged to enable wireless sensor networks, which necessitates power conditioning of the AC output. Piezoelectric beam-type bending mode energy harvesters or other devices that operate using a piezoelectric element at resonance produce high voltage levels, for which AC-DC converters and step-down DC-DC converters have been previously investigated. However, for piezoelectric stack energy harvesters operating off-resonance and producing low voltage outputs, a step-up circuit is required for power conditioning, such as seen in electromagnetic vibration energy scavengers, RF communications, and MEMS harvesters. This paper theoretically and experimentally investigates power conditioning of a low-voltage piezoelectric stack energy harvester.

  6. COUPLED ANALYSIS FOR THE HARVESTING STRUCTURE AND THE MODULATING CIRCUIT IN A PIEZOELECTRIC BIMORPH ENERGY HARVESTER

    Institute of Scientific and Technical Information of China (English)

    Yuantai Hu; Ting Hu; Qing Jiang

    2007-01-01

    The authors analyze a piezoelectric energy harvester as an electro-mechanically coupled system. The energy harvester consists of a piezoelectric bimorph with a concentrated mass attached at one end, called the harvesting structure, an electric circuit for energy storage,and a rectifier that converts the AC output of the harvesting structure into a DC input for the storage circuit. The piezoelectric bimorph is assumed to be driven into flexural vibration by an ambient acoustic source to convert the mechanical energies into electric energies. The analysis indicates that the performance of this harvester, measured by the power density, is characterized by three important non-dimensional parameters, I.e., the non-dimensional inductance of the storage circuit, the non-dimensional aspect ratio (length/thickness) and the non-dimensional end mass of the harvesting structure. The numerical results show that: (1) the power density can be optimized by varying the non-dimensional inductance for each fixed non-dimensional aspect ratio with a fixed non-dimensional end mass; and (2) for a fixed non-dimensional inductance, the power density is maximized if the non-dimensional aspect ratio and the non-dimensional end mass are so chosen that the harvesting structure, consisting of both the piezoelectric bimorph and the end mass attached, resonates at the frequency of the ambient acoustic source.

  7. Energy-driven computing for energy-harvesting embedded systems

    OpenAIRE

    Merrett, Geoff V.

    2016-01-01

    There has been increasing interest over the last decade in the powering of embedded systems from ‘harvested’ energy, and this has been further fuelled by the promise and vision of IoT. Energy harvesting systems present numerous challenges, although some of these are also posed by their battery-powered counterparts: e.g. ultra-low power consumption. However, a significant challenge not witnessed in battery-powered systems is a requirement to manage the combination of a highly unpredictable and...

  8. Metamaterial electromagnetic energy harvester with high selective harvesting for left- and right-handed circularly polarized waves

    Science.gov (United States)

    Shang, Shuai; Yang, Shizhong; Liu, Jing; Shan, Meng; Cao, Hailin

    2016-07-01

    In this paper, a metamaterial electromagnetic energy harvester constructed via the capacitive loading of metal circular split rings is presented. Each energy-harvesting cell is loaded with a resistance that imitates the input impedance of a rectifier circuit. Specifically, the metamaterial energy harvester has high selective harvesting for left- and right-handed circularly polarized waves. Here, the energy absorption is mostly induced by the resistive load; thus, effective energy harvesting can be achieved. Moreover, the proposed energy harvester exhibits a high-efficiency harvesting for right-handed circularly polarized waves over a wide range of incident angles. Further, a transmission line model is adopted to interpret the energy harvesting mechanism, which shows that a good impedance matching and low dielectric loss can further enhance the harvesting efficiency. To demonstrate the design, a 15 × 15 unit-cell prototype is fabricated and measured, and the measured results reasonably agree with the simulated ones.

  9. The case for energy harvesting on wildlife in flight

    Science.gov (United States)

    Shafer, Michael W.; MacCurdy, Robert; Shipley, J. Ryan; Winkler, David; Guglielmo, Christopher G.; Garcia, Ephrahim

    2015-02-01

    The confluence of advancements in microelectronic components and vibrational energy harvesting has opened the possibility of remote sensor units powered solely from the motion of their hosts. There are numerous applications of such systems, including the development of modern wildlife tracking/data-logging devices. These ‘bio-logging’ devices are typically mass-constrained because they must be carried by an animal. Thus, they have historically traded scientific capability for operational longevity due to restrictions on battery size. Recently, the precipitous decrease in the power requirements of microelectronics has been accompanied by advancements in the area of piezoelectric vibrational energy harvesting. These energy harvesting devices are now capable of powering the type of microelectronic circuits used in bio-logging devices. In this paper we consider the feasibility of employing these vibrational energy harvesters on flying vertebrates for the purpose of powering a bio-logging device. We show that the excess energy available from birds and bats could be harvested without adversely affecting their overall energy budget. We then present acceleration measurements taken on flying birds in a flight tunnel to understand modulation of flapping frequency during steady flight. Finally, we use a recently developed method of estimating the maximum power output from a piezoelectric energy harvester to determine the amount of power that could be practically harvested from a flying bird. The results of this analysis show that the average power output of a piezoelectric energy harvester mounted to a bird or bat could produce more than enough power to run a bio-logging device. We compare the power harvesting capabilities to the energy requirements of an example system and conclude that vibrational energy harvesting on flying birds and bats is viable and warrants further study, including testing.

  10. Vibration energy harvesting from random force and motion excitations

    Science.gov (United States)

    Tang, Xiudong; Zuo, Lei

    2012-07-01

    A vibration energy harvester is typically composed of a spring-mass system with an electromagnetic or piezoelectric transducer connected in parallel with a spring. This configuration has been well studied and optimized for harmonic vibration sources. Recently, a dual-mass harvester, where two masses are connected in series by the energy transducer and a spring, has been proposed. The dual-mass vibration energy harvester is proved to be able to harvest more power and has a broader bandwidth than the single-mass configuration, when the parameters are optimized and the excitation is harmonic. In fact, some dual-mass vibration energy harvesters, such as regenerative vehicle suspensions and buildings with regenerative tuned mass dampers (TMDs), are subjected to random excitations. This paper is to investigate the dual-mass and single-mass vibration harvesters under random excitations using spectrum integration and the residue theorem. The output powers for these two types of vibration energy harvesters, when subjected to different random excitations, namely force, displacement, velocity and acceleration, are obtained analytically with closed-form expressions. It is also very interesting to find that the output power of the vibration energy harvesters under random excitations depends on only a few parameters in very simple and elegant forms. This paper also draws some important conclusions on regenerative vehicle suspensions and buildings with regenerative TMDs, which can be modeled as dual-mass vibration energy harvesters. It is found that, under white-noise random velocity excitation from road irregularity, the harvesting power from vehicle suspensions is proportional to the tire stiffness and road vertical excitation spectrum only. It is independent of the chassis mass, tire-wheel mass, suspension stiffness and damping coefficient. Under random wind force excitation, the power harvested from buildings with regenerative TMD will depends on the building mass only, not

  11. Fabrication of SU-8 low frequency electrostatic energy harvester

    KAUST Repository

    Ramadan, Khaled S.

    2011-11-01

    A 1500μm × 1500μm × 150μm out-of-plane, gap closing, electrostatic energy harvester is designed and fabricated to harvest low-frequency ambient vibrations. SU-8 is used to fabricate the proof mass (1200μm × 1200μm × 150μm) and the 5 m springs. Different harvesters were designed to harvest at 50, 75 and 110 Hz. At 110 Hz, Simulations show that with an input vibration of 10 μm amplitude at the frequency of resonance of the structure, the energy harvester should generate an average output power density of 0.032μW/mm3. This is the most area-efficient low-frequency electrostatic harvester to-date. © 2011 IEEE.

  12. A Novel Ropes-DrivenWideband Piezoelectric Vibration Energy Harvester

    Directory of Open Access Journals (Sweden)

    Jinhui Zhang

    2016-12-01

    Full Text Available This paper presents a novel piezoelectric vibration energy harvester (PVEH in which a high-frequency generating beam (HFGB is driven by an array of low-frequency driving beams (LFDBs using ropes. Two mechanisms based on frequency upconversion and multimodal harvesting work together to broaden the frequency bandwidth of the proposed vibration energy harvester (VEH. The experimental results show that the output power of generating beam (GB remains unchanged with the increasing number of driving beams (DBs, compared with the traditional arrays of beams vibration energy harvester (AB-VEH, and the output power and bandwidth behavior can be adjusted by parameters such as acceleration, rope margin, and stiffness of LFDBs, which shows the potential to achieve unlimited wideband vibration energy-harvesting for a variable environment.

  13. Solar/Electromagnetic Energy Harvesting and Wireless Power Transmission

    OpenAIRE

    2014-01-01

    This paper presents a review of existing works and solutions in the field of solar/electromagnetic energy harvesting and wireless power transmission. More specifically, the paper covers: solar/electromagnetic harvesters where solar antenna structures are used to obtain a compact implementation, direct current (dc) combining circuits necessary to combine the outputs of the solar and the electromagnetic harvesters, and efficient solar-to-electromagnetic (EM) converters that can be used to synth...

  14. HARVESTED ENERGY-ADAPTIVE MAC PROTOCOL FOR ENERGY HARVESTING IOT NETWORKS

    Directory of Open Access Journals (Sweden)

    Hyeong-Kyu Lee

    2015-12-01

    Full Text Available In energy harvesting IoT networks, an energy queue state of an IoT device will change dynamically and the number of IoT devices that transmit data to the IoT AP will vary in a frame. So we need a MAC protocol to adjust the frame length taking the amount of energy of IoT devices into consideration. Since the existing Framed slotted ALOHA (F-ALOHA Medium Access Control (MAC protocol utilizes the fixed frame size, the resource efficiency can be reduced. In this paper, we propose a Harvested Energy-adaptive Medium Access Control (HEMAC protocol where an IoT Access Point (AP allocates slots in accordance with the number of IoT devices that try to transmit data in a frame. The proposed HE-MAC protocol improves the resource efficiency of the F-ALOHA MAC protocol. We show that the resource efficiency of the HE-MAC protocol is superior to those of the F-ALOHA MAC protocol through simulations.

  15. Ecological impacts of energy-wood harvests: lessons from whole-tree harvesting and natural disturbance

    Science.gov (United States)

    Berger, Alaina L.; Palik, Brian; D'Amato, Anthony W.; Fraver, Shawn; Bradford, John B.; Nislow, Keith H.; King, David; Brooks, Robert T.

    2013-01-01

    Recent interest in using forest residues and small-diameter material for biofuels is generating a renewed focus on harvesting impacts and forest sustainability. The rich legacy of research from whole-tree harvesting studies can be examined in light of this interest. Although this research largely focused on consequences for forest productivity, in particular carbon and nutrient pools, it also has relevance for examining potential consequences for biodiversity and aquatic ecosystems. This review is framed within a context of contrasting ecosystem impacts from whole-tree harvesting because it represents a high level of biomass removal. Although whole-tree harvesting does not fully use the nonmerchantable biomass available, it indicates the likely direction and magnitude of impacts that can occur through energy-wood harvesting compared with less-intensive conventional harvesting and to dynamics associated with various natural disturbances. The intent of this comparison is to gauge the degree of departure of energy-wood harvesting from less intensive conventional harvesting. The review of the literature found a gradient of increasing departure in residual structural conditions that remained in the forest when conventional and whole-tree harvesting was compared with stand-replacing natural disturbance. Important stand- and landscape-level processes were related to these structural conditions. The consequence of this departure may be especially potent because future energy-wood harvests may more completely use a greater range of forest biomass at potentially shortened rotations, creating a great need for research that explores the largely unknown scale of disturbance that may apply to our forest ecosystems.

  16. Energy Harvesting Cycles of Dielectric ElectroActive Polymer Generators

    DEFF Research Database (Denmark)

    Dimopoulos, Emmanouil; Trintis, Ionut; Munk-Nielsen, Stig

    2012-01-01

    Energy harvesting via Dielectric ElectroActive Polymer (DEAP) generators has attracted much of the scientific interest over the past few years, mainly due to the advantages that these smart materials offer against competing technologies, as electromagnetic generators and piezoelectrics....... Their higher energy density, superior low-speed performance, light-weighted nature as well as their shapely structure have rendered DEAPs candidate solutions for various actuation and energy harvesting applications. In this paper, a thoroughly analysis of all energy harvesting operational cycles of a DEAP...

  17. Characterizing the effective bandwidth of tri-stable energy harvesters

    Science.gov (United States)

    Panyam, Meghashyam; Daqaq, Mohammed F.

    2017-01-01

    Recently, it has been shown that nonlinear vibratory energy harvesters possessing a tri-stable potential function are capable of harvesting energy efficiently over a wider range of frequencies in comparison to harvesters with a double-well potential function. However, the effect of the design parameters of the harvester on the dynamic response and the effective bandwidth of such devices remains uninvestigated. To fill this void, this paper establishes an analytical approach to characterize the effective frequency bandwidth of harvesters that possess a hexic potential energy function. To achieve this goal, the method of multiple scales is utilized to construct analytical solutions describing the amplitude and stability of the intra- and inter-well dynamics of the harvester. Using these solutions, critical bifurcations in the parameter's space are identified and used to define an effective frequency bandwidth of the harvester. The influence of the electric parameters, namely, the time constant ratio (ratio between the period of the mechanical system and the time constant of the harvesting circuit) and the electromechanical coupling, on the effective frequency bandwidth is analyzed. Experimental studies performed on the harvester are presented to validate some of the theoretical findings.

  18. Comparison of the dielectric electroactive polymer generator energy harvesting cycles

    DEFF Research Database (Denmark)

    Dimopoulos, Emmanouil; Trintis, Ionut; Munk-Nielsen, Stig

    2013-01-01

    The Dielectric ElectroActive Polymer (DEAP) generator energy harvesting cycles have been in the spotlight of the scientific interest for the past few years. Indeed, several articles have demonstrated thorough and comprehensive comparisons of the generator fundamental energy harvesting cycles......, namely Constant Charge (CC), Constant Voltage (CV) and Constant E-field (CE), based on averaged theoretical models. Yet, it has not been possible until present to validate the outcome of those comparisons via respective experimental results. In this paper, all three primary energy harvesting cycles...... are experimentally compared, based upon the coupling of a DEAP generator with a bidirectional non-isolated power electronic converter, by means of energy gain, energy harvesting efficiency and energy conversion efficiency....

  19. Optimal Energy Harvesting from Vortex-Induced Vibrations of Cables

    CERN Document Server

    Antoine, G O; Michelin, S

    2016-01-01

    Vortex-induced vibrations (VIV) of flexible cables are an example of flow-induced vibrations that can act as energy harvesting systems by converting energy associated with the spontaneous cable motion into electricity. This work investigates the optimal positioning of the harvesting devices along the cable, using numerical simulations with a wake oscillator model to describe the unsteady flow forcing. Using classical gradient-based optimization, the optimal harvesting strategy is determined for the generic configuration of a flexible cable fixed at both ends, including the effect of flow forces and gravity on the cable's geometry. The optimal strategy is found to consist systematically in a concentration of the harvesting devices at one of the cable's ends, relying on deformation waves along the cable to carry the energy toward this harvesting site. Furthermore, we show that the performance of systems based on VIV of flexible cables is significantly more robust to flow velocity variations, in comparison with ...

  20. Axial Permanent Magnet Generator for Wearable Energy Harvesting

    DEFF Research Database (Denmark)

    Högberg, Stig; Sødahl, Jakob Wagner; Mijatovic, Nenad

    2016-01-01

    An increasing demand for battery-free electronics is evident by the rapid increase of wearable devices, and the design of wearable energy harvesters follows accordingly. An axial permanent magnet generator was designed to harvest energy from human body motion and supplying it to a wearable......W, respectively) with an iron yoke is subject to losses that exceed the realistic input power, and was therefore deemed infeasible. A generator without the iron yoke was concluded to perform well as a wearable energy harvester. An experimental investigation of a prototype revealed an output power of almost 1 m...

  1. An Electromagnetic MEMS Energy Harvester Array with Multiple Vibration Modes

    Directory of Open Access Journals (Sweden)

    Huicong Liu

    2015-07-01

    Full Text Available This paper reports the design, micromachining and characterization of an array of electromagnetic energy harvesters (EHs with multiple frequency peaks. The authors present the combination of three multi-modal spring-mass structures so as to realize at least nine resonant peaks within a single microelectromechanical systems (MEMS chip. It is assembled with permanent magnet to show an electromagnetic-based energy harvesting capability. This is the first demonstration of multi-frequency MEMS EH existing with more than three resonant peaks within a limited frequency range of 189 to 662 Hz. It provides a more effective approach to harvest energy from the vibration sources of multiple frequency peaks.

  2. Communication strategies for two models of discrete energy harvesting

    DEFF Research Database (Denmark)

    Trillingsgaard, Kasper Fløe; Popovski, Petar

    2014-01-01

    Energy harvesting is becoming a viable option for powering small wireless devices. Energy for data transmission is supplied by the nature, such that when a transmission is about to take place in an arbitrary instant, the amount of available energy is a random quantity. The arrived energy is stored...... in a battery and transmissions are interrupted if the battery runs out of energy. We address communication in slot-based energy harvesting systems, where the transmitter communicates with ON-OFF signaling: in each slot it can either choose to transmit (ON) or stay silent (OFF). Two different models...... of harvesting and communication are addressed. In the first model an energy quantum can arrive, with a certain probability, in each slot. The second model is based on a frame of size F: energy arrives periodically over F slots, in batches containing a random number of energy quanta. We devise achievable...

  3. Energy harvesting performance of a broadband electromagnetic vibration energy harvester for powering industrial wireless sensor networks

    Science.gov (United States)

    Ren, Long; Chen, Renwen; Xia, Huakang; Zhang, Xiaoxiao

    2016-04-01

    To supply power to wireless sensor networks, a type of broadband electromagnetic vibration energy harvester (VEH) using bistable vibration scavenging structure is proposed. It consists of a planar spring, an electromagnetic transducer with an annular magnetic circuit, and a coil assembly with a ferrite bobbin inside. A nonlinear magnetic force respecting to the relative displacement is generated by the ferrite bobbin, and to broaden the working frequency bandwidth of the VEH. Moreover, the ferrite bobbin increases the magnetic flux linkage gradient of the coil assembly in its moving region, and further to improve its output voltage. The dynamic behaviors of the VEH are analyzed and predicted by finite element analysis and ODE calculation. Validation experiments are carried out and show that the VEH can harvest high energy in a relatively wide excitation frequency band. The further test shows that the load power of the VEH with a load resistor of 90Ω can reach 10mW level in a wide frequency bandwidth when the acceleration level of the harmonic excitation is 1g. It can ensure the intermittent work of many sensors as well as wireless communication modules at least.

  4. Joint Resource Allocation of Spectrum Sensing and Energy Harvesting in an Energy-Harvesting-Based Cognitive Sensor Network.

    Science.gov (United States)

    Liu, Xin; Lu, Weidang; Ye, Liang; Li, Feng; Zou, Deyue

    2017-03-16

    The cognitive sensor (CS) can transmit data to the control center in the same spectrum that is licensed to the primary user (PU) when the absence of the PU is detected by spectrum sensing. However, the battery energy of the CS is limited due to its small size, deployment in atrocious environments and long-term working. In this paper, an energy-harvesting-based CS is described, which senses the PU together with collecting the radio frequency energy to supply data transmission. In order to improve the transmission performance of the CS, we have proposed the joint resource allocation of spectrum sensing and energy harvesting in the cases of a single energy-harvesting-based CS and an energy-harvesting-based cognitive sensor network (CSN), respectively. Based on the proposed frame structure, we have formulated the resource allocation as a class of joint optimization problems, which seek to maximize the transmission rate of the CS by jointly optimizing sensing time, harvesting time and the numbers of sensing nodes and harvesting nodes. Using the half searching method and the alternating direction optimization, we have achieved the sub-optimal solution by converting the joint optimization problem into several convex sub-optimization problems. The simulation results have indicated the predominance of the proposed energy-harvesting-based CS and CSN models.

  5. A universal self-charging system driven by random biomechanical energy for sustainable operation of mobile electronics

    Science.gov (United States)

    Niu, Simiao; Wang, Xiaofeng; Yi, Fang; Zhou, Yu Sheng; Wang, Zhong Lin

    2015-12-01

    Human biomechanical energy is characterized by fluctuating amplitudes and variable low frequency, and an effective utilization of such energy cannot be achieved by classical energy-harvesting technologies. Here we report a high-efficient self-charging power system for sustainable operation of mobile electronics exploiting exclusively human biomechanical energy, which consists of a high-output triboelectric nanogenerator, a power management circuit to convert the random a.c. energy to d.c. electricity at 60% efficiency, and an energy storage device. With palm tapping as the only energy source, this power unit provides a continuous d.c. electricity of 1.044 mW (7.34 W m-3) in a regulated and managed manner. This self-charging unit can be universally applied as a standard `infinite-lifetime' power source for continuously driving numerous conventional electronics, such as thermometers, electrocardiograph system, pedometers, wearable watches, scientific calculators and wireless radio-frequency communication system, which indicates the immediate and broad applications in personal sensor systems and internet of things.

  6. Harvesting under transient conditions: harvested energy as a proxy for optimal resonance frequency detuning

    Science.gov (United States)

    Hynds, Taylor D.; Kauffman, Jeffrey L.

    2015-04-01

    Piezoelectric-based vibration energy harvesting is of interest in a wide range of applications, and a number of harvesting schemes have been proposed and studied { primarily when operating under steady state conditions. However, energy harvesting behavior is rarely studied in systems with transient excitations. This paper will work to develop an understanding of this behavior within the context of a particular vibration reduction technique, resonance frequency detuning. Resonance frequency detuning provides a method of reducing mechanical response at structural resonances as the excitation frequency sweeps through a given range. This technique relies on switching the stiffness state of a structure at optimal times to detune its resonance frequency from that of the excitation. This paper examines how this optimal switch may be triggered in terms of the energy harvested, developing a normalized optimal switch energy that is independent of the open- and short-circuit resistances. Here the open- and short-circuit shunt resistances refer to imposed conditions that approximate the open- and short-circuit conditions, via high and low resistance shunts. These conditions are practically necessary to harvest the small amounts of power needed to switch stiffness states, as open-circuit and closed-circuit refer to infinite resistance and zero resistance, respectively, and therefore no energy passes through the harvesting circuit. The limiting stiffness states are then defined by these open- and short-circuit resistances. The optimal switch energy is studied over a range of sweep rates, damping ratios, and coupling coefficients; it is found to increase with the coupling coefficient and decrease as the sweep rate and damping ratio increase, behavior which is intuitive. Higher coupling means more energy is converted by the piezoelectric material, and therefore more energy is harvested in a given time; an increased sweep rate means resonance is reached sooner, and there will less

  7. Performance Study of Diagonally Segmented Piezoelectric Vibration Energy Harvester

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jae Eun [Catholic Univ. of Daegu, Daegu (Korea, Republic of)

    2013-08-15

    This study proposes a piezoelectric vibration energy harvester composed of two diagonally segmented energy harvesting units. An auxiliary structural unit is attached to the tip of a host structural unit cantilevered to a vibrating base, where the two components have beam axes in opposite directions from each other and matched short-circuit resonant frequencies. Contrary to the usual observations in two resonant frequency-matched structures, the proposed structure shows little eigenfrequency separation and yields a mode sequence change between the first two modes. These lead to maximum power generation around a specific frequency. By using commercial finite element software, it is shown that the magnitude of the output power from the proposed vibration energy harvester can be substantially improved in comparison with those from conventional cantilevered energy harvesters with the same footprint area and magnitude of a tip mass.

  8. Resource management for energy and spectrum harvesting sensor networks

    CERN Document Server

    Zhang, Deyu; Zhou, Haibo; Shen, Xuemin (Sherman)

    2017-01-01

    This SpringerBrief offers a comprehensive review and in-depth discussion of the current research on resource management. The authors explain how to best utilize harvested energy and temporally available licensed spectrum. Throughout the brief, the primary focus is energy and spectrum harvesting sensor networks (ESHNs) including energy harvesting (EH)-powered spectrum sensing and dynamic spectrum access. To efficiently collect data through the available licensed spectrum, this brief examines the joint management of energy and spectrum. An EH-powered spectrum sensing and management scheme for Heterogeneous Spectrum Harvesting Sensor Networks (HSHSNs) is presented in this brief. The scheme dynamically schedules the data sensing and spectrum access of sensors in ESHSNs to optimize the network utility, while considering the stochastic nature of EH process, PU activities and channel conditions. This brief also provides useful insights for the practical resource management scheme design for ESHSNs and motivates a ne...

  9. Energy Harvesting Using an Analog Circuit under Multimodal Vibration

    Directory of Open Access Journals (Sweden)

    Shigeru Shimose

    2013-01-01

    Full Text Available The efficiency of harvesting energy from a vibrating structure using a piezoelectric transducer and a simple analog circuit is investigated experimentally. This analog circuit was originally invented for a synchronized switch damping on inductor (SSDI technique, which enhances the damping of mechanical vibration. In this study, the circuit is used to implement a synchronized switch harvesting on inductor (SSHI technique. A multiple degree of freedom (MDOF structure is excited by single sinusoidal forces at its resonant frequencies and by random forces. The piezoelectric transducer converts this mechanical energy into electrical energy which is harvested using a standard rectifier bridge circuit with and without our analog circuit. Experimental results show that our analog circuit makes it possible to harvest twice as much energy under both single sinusoidal and random vibration excitations.

  10. Energy harvesting from low frequency applications using piezoelectric materials

    Energy Technology Data Exchange (ETDEWEB)

    Li, Huidong; Tian, Chuan; Deng, Z. Daniel, E-mail: zhiqun.deng@pnnl.gov [Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99352 (United States)

    2014-12-15

    In an effort to eliminate the replacement of the batteries of electronic devices that are difficult or impractical to service once deployed, harvesting energy from mechanical vibrations or impacts using piezoelectric materials has been researched over the last several decades. However, a majority of these applications have very low input frequencies. This presents a challenge for the researchers to optimize the energy output of piezoelectric energy harvesters, due to the relatively high elastic moduli of piezoelectric materials used to date. This paper reviews the current state of research on piezoelectric energy harvesting devices for low frequency (0–100 Hz) applications and the methods that have been developed to improve the power outputs of the piezoelectric energy harvesters. Various key aspects that contribute to the overall performance of a piezoelectric energy harvester are discussed, including geometries of the piezoelectric element, types of piezoelectric material used, techniques employed to match the resonance frequency of the piezoelectric element to input frequency of the host structure, and electronic circuits specifically designed for energy harvesters.

  11. Energy harvesting from mastication forces via a smart tooth

    Science.gov (United States)

    Bani-Hani, Muath; Karami, M. Amin

    2016-04-01

    The batteries of the current pacing devices are relatively large and occupy over 60 percent of the size of pulse generators. Therefore, they cannot be placed in the subtle areas of human body. In this paper, the mastication force and the resulting tooth pressure are converted to electricity. The pressure energy can be converted to electricity by using the piezoelectric effect. The tooth crown is used as a power autonomous pulse generator. We refer to this envisioned pulse generator as the smart tooth. The smart tooth is in the form of a dental implant. A piezoelectric vibration energy harvester is designed and modeled for this purpose. The Piezoelectric based energy harvesters investigated and analyzed in this paper initially includes a single degree of freedom piezoelectric based stack energy harvester which utilizes a harvesting circuit employing the case of a purely resistive circuit. The next step is utilizing and investigating a bimorph piezoelectric beam which is integrated/embedded in the smart tooth implant. Mastication process causes the bimorph beam to buckle or return to unbuckled condition. The transitions results in vibration of the piezoelectric beam and thus generate energy. The power estimated by the two mechanisms is in the order of hundreds of microwatts. Both scenarios of the energy harvesters are analytically modeled. The exact analytical solution of the piezoelectric beam energy harvester with Euler-Bernoulli beam assumptions is presented. The electro-mechanical coupling and the geometric nonlinearities have been included in the model for the piezoelectric beam.

  12. MEMS-based thick film PZT vibrational energy harvester

    DEFF Research Database (Denmark)

    Lei, Anders; Xu, Ruichao; Thyssen, Anders

    2011-01-01

    We present a MEMS-based unimorph silicon/PZT thick film vibrational energy harvester with an integrated proof mass. We have developed a process that allows fabrication of high performance silicon based energy harvesters with a yield higher than 90%. The process comprises a KOH etch using...... a mechanical front side protection of an SOI wafer with screen printed PZT thick film. The fabricated harvester device produces 14.0 μW with an optimal resistive load of 100 kΩ from 1g (g=9.81 m s-2) input acceleration at its resonant frequency of 235 Hz....

  13. An innovative tri-directional broadband piezoelectric energy harvester

    Energy Technology Data Exchange (ETDEWEB)

    Su, Wei-Jiun, E-mail: weijiun@mie.utoronto.ca; Zu, Jean [Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, Ontario M5S 3G8 (Canada)

    2013-11-11

    This paper presents a tri-directional piezoelectric energy harvester that is able to harvest vibration energy over a wide bandwidth from three orthogonal directions. The harvester consists of a main beam, an auxiliary beam, and a spring-mass system, with magnets integrated to introduce nonlinear force and couple the three sub-systems. Theoretical analysis and experiments were performed at constant acceleration under frequency sweeps to acquire frequency responses. The experimental results show that the voltage can achieve more than 2 V over more than 5 Hz of bandwidth with 1 MΩ load in the three orthogonal directions.

  14. Analysis of AC Low-Voltage Energy Harvesting

    Science.gov (United States)

    2014-09-01

    to harness wasted vibrational energy. Some of these applications include inserting a piezoelectric harvester in shoes to supply small amounts of...harness wasted vibrational energy. Some of these applications include inserting a piezoelectric harvester in shoes to supply small amounts of power to...10]). ..........................8  Figure 8.  The relationship between the duty cycle and current (from [10]). ....................9  Figure 9.  DCM

  15. Effect of Polarization Fatigue on Harvesting Energy Using Pyroelectric Materials

    Directory of Open Access Journals (Sweden)

    Saber Mohammadi

    2014-01-01

    Full Text Available The phenomenon of polarization fatigue in ferroelectric materials is defined and the effect of this phenomenon on harvested energy using these materials has been studied. In order to illustrate this effect, the harvested energy using PZN-4.5PT single crystal was compared in two cases of fatigued and nonfatigued samples. The results have been calculated between two temperatures of 100 and 130°C using Ericsson thermodynamic cycle.

  16. Development of MEMS based pyroelectric thermal energy harvesters

    Science.gov (United States)

    Hunter, Scott R.; Lavrik, Nickolay V.; Bannuru, Thirumalesh; Mostafa, Salwa; Rajic, Slo; Datskos, Panos G.

    2011-06-01

    The efficient conversion of waste thermal energy into electrical energy is of considerable interest due to the huge sources of low-grade thermal energy available in technologically advanced societies. Our group at the Oak Ridge National Laboratory (ORNL) is developing a new type of high efficiency thermal waste heat energy converter that can be used to actively cool electronic devices, concentrated photovoltaic solar cells, computers and large waste heat producing systems, while generating electricity that can be used to power remote monitoring sensor systems, or recycled to provide electrical power. The energy harvester is a temperature cycled pyroelectric thermal-to-electrical energy harvester that can be used to generate electrical energy from thermal waste streams with temperature gradients of only a few degrees. The approach uses a resonantly driven pyroelectric capacitive bimorph cantilever structure that potentially has energy conversion efficiencies several times those of any previously demonstrated pyroelectric or thermoelectric thermal energy harvesters. The goals of this effort are to demonstrate the feasibility of fabricating high conversion efficiency MEMS based pyroelectric energy converters that can be fabricated into scalable arrays using well known microscale fabrication techniques and materials. These fabrication efforts are supported by detailed modeling studies of the pyroelectric energy converter structures to demonstrate the energy conversion efficiencies and electrical energy generation capabilities of these energy converters. This paper reports on the modeling, fabrication and testing of test structures and single element devices that demonstrate the potential of this technology for the development of high efficiency thermal-to-electrical energy harvesters.

  17. Experimental study of energy harvesting in UHF band

    Science.gov (United States)

    Bernacki, Ł.; Gozdur, R.; Salamon, N.

    2016-04-01

    A huge progress of down-sizing technology together with trend of decreasing power consumption and, on the other hand, increasing efficiency of electronics give the opportunity to design and to implement the energy harvesters as main power sources. This paper refers to the energy that can be harvested from electromagnetic field in the unlicensed frequency bands. The paper contains description of the most popular techniques and transducers that can be applied in energy harvesting domain. The overview of current research and commercial solutions was performed for bands in ultra-high frequency range, which are unlicensed and where transmission is not limited by administrative arrangements. During the experiments with Powercast’s receiver, the same bands as sources of electromagnetic field were taken into account. This power source is used for conducting radio-communication process and excess energy could be used for powering the extra electronic circuits. The paper presents elaborated prototype of energy harvesting system and the measurements of power harvested in ultra-high frequency range. The evaluation of RF energy harvesters for powering ultra-low power (ULP) electronic devices was performed based on survey and results of the experiments.

  18. Airflow energy harvesting with high wind velocities for industrial applications

    Science.gov (United States)

    Chew, Z. J.; Tuddenham, S. B.; Zhu, M.

    2016-11-01

    An airflow energy harvester capable of harvesting energy from vortices at high speed is presented in this paper. The airflow energy harvester is implemented using a modified helical Savonius turbine and an electromagnetic generator. A power management module with maximum power point finding capability is used to manage the harvested energy and convert the low voltage magnitude from the generator to a usable level for wireless sensors. The airflow energy harvester is characterized using vortex generated by air hitting a plate in a wind tunnel. By using an aircraft environment with wind speed of 17 m/s as case study, the output power of the airflow energy harvester is measured to be 126 mW. The overall efficiency of the power management module is 45.76 to 61.2%, with maximum power point tracking efficiency of 94.21 to 99.72% for wind speed of 10 to 18 m/s, and has a quiescent current of 790 nA for the maximum power point tracking circuit.

  19. Development of enhanced piezoelectric energy harvester induced by human motion.

    Science.gov (United States)

    Minami, Y; Nakamachi, E

    2012-01-01

    In this study, a high frequency piezoelectric energy harvester converted from the human low vibrated motion energy was newly developed. This hybrid energy harvester consists of the unimorph piezoelectric cantilever and a couple of permanent magnets. One magnet was attached at the end of cantilever, and the counterpart magnet was set at the end of the pendulum. The mechanical energy provided through the human walking motion, which is a typical ubiquitous presence of vibration, is converted to the electric energy via the piezoelectric cantilever vibration system. At first, we studied the energy convert mechanism and the performance of our energy harvester, where the resonance free vibration of unimorph cantilever with one permanent magnet under a rather high frequency was induced by the artificial low frequency vibration. The counterpart magnet attached on the pendulum. Next, we equipped the counterpart permanent magnet pendulum, which was fluctuated under a very low frequency by the human walking, and the piezoelectric cantilever, which had the permanent magnet at the end. The low-to-high frequency convert "hybrid system" can be characterized as an enhanced energy harvest one. We examined and obtained maximum values of voltage and power in this system, as 1.2V and 1.2 µW. Those results show the possibility to apply for the energy harvester in the portable and implantable Bio-MEMS devices.

  20. Evaluating vehicular-induced bridge vibrations for energy harvesting applications

    Science.gov (United States)

    Reichenbach, Matthew; Fasl, Jeremiah; Samaras, Vasilis A.; Wood, Sharon; Helwig, Todd; Lindenberg, Richard

    2012-04-01

    Highway bridges are vital links in the transportation network in the United States. Identifying possible safety problems in the approximately 600,000 bridges across the country is generally accomplished through labor-intensive, visual inspections. Ongoing research sponsored by NIST seeks to improve inspection practices by providing real-time, continuous monitoring technology for steel bridges. A wireless sensor network with a service life of ten years that is powered by an integrated energy harvester is targeted. In order to achieve the target ten-year life for the monitoring system, novel approaches to energy harvesting for use in recharging batteries are investigated. Three main sources of energy are evaluated: (a) vibrational energy, (b) solar energy, and (c) wind energy. Assessing the energy produced from vehicular-induced vibrations and converted through electromagnetic induction is the focus of this paper. The goal of the study is to process acceleration data and analyze the vibrational response of steel bridges to moving truck loads. Through spectral analysis and harvester modeling, the feasibility of vibration-based energy harvesting for longterm monitoring can be assessed. The effects of bridge conditions, ambient temperature, truck traffic patterns, and harvester position on the power content of the vibrations are investigated. With sensor nodes continually recharged, the proposed real-time monitoring system will operate off the power grid, thus reducing life cycle costs and enhancing inspection practices for state DOTs. This paper will present the results of estimating the vibration energy of a steel bridge in Texas.

  1. Enhancing ability of harvesting energy from random vibration by decreasing the potential barrier of bistable harvester

    Science.gov (United States)

    Lan, Chunbo; Qin, Weiyang

    2017-02-01

    When a bistable energy harvester (BEH) is driven by weak random excitation, its harvesting efficiency will decrease due to the seldom occurrence of interwell motion. To overcome this defect, we developed an improved bistable energy harvester (IBEH) from BEH by adding a small magnet at the middle of two fixed magnets. It is proved that the attractive force originated from the additional magnet can pull down the potential barrier and shallow the potential well, but still keep the middle position of beam unstable. This can make jumping between potential wells easier. Thus IBEH can realize snap-through even at fairly weak excitation. The magnetic potential energy is given and the electromechanical equations are derived. Then the harvesting performance of IBEH under random excitation is studied. Validation experiments are designed and carried out. Comparisons prove that IBEH is preferable to BEH in harvesting random energy and can give out a high output voltage even at weak excitation. The size of additional magnet can be optimized to reach the best performance of IBEH.

  2. A triboelectric wind turbine for small-scale energy harvesting

    Science.gov (United States)

    Perez, Matthias; Boisseau, Sebastien; Geisler, Matthias; Despesse, Ghislain; Reboud, Jean Luc

    2016-11-01

    This paper deals with a rotational energy harvester including a Horizontal Axis Wind Turbine (HAWT), a cylindrical stator covered by several electrodes, and thin Teflon dielectric membranes hung on the rotor. The sliding contact of the Teflon membranes on the stator provides simultaneously large capacitance variations and a polarization source for the electrostatic converter by exploiting triboelectric phenomena. 1μW has been harvested at 4m/s; 130μW at 10m/s and 550μW at 20m/s with a 40mmØ device. In order to validate the energy harvesting chain, the airflow energy harvester has been connected to a power management circuit implementing Synchronous Electric Charge Extraction (SECE) to supply a wireless sensor node with temperature and acceleration measurements, transmitted to a computer at 868MHz.

  3. Energy harvesting in a quad-stable harvester subjected to random excitation

    Directory of Open Access Journals (Sweden)

    Zhi-yong Zhou

    2016-02-01

    Full Text Available In response to the defects of bi-stable energy harvester (BEH, we develop a novel quad-stable energy harvester (QEH to improve harvesting efficiency. The device is made up of a bimorph cantilever beam having a tip magnet and three external fixed magnets. By adjusting the positions of the fixed magnets and the distances between the tip magnet and the fixed ones, the quad-stable equilibrium positions can emerge. The potential energy shows that the barriers of the QEH are lower than those of the BEH for the same separation distance. Experiment results reveal that the QEH can realize snap-through easier and make a dense snap-through in response under random excitation. Moreover, its strain and voltage both become large for snap-through between the nonadjacent stable positions. There exists an optimal separation distance for different excitation intensities.

  4. An improved stability characterization for aeroelastic energy harvesting applications

    Science.gov (United States)

    Javed, U.; Abdelkefi, A.; Akhtar, I.

    2016-07-01

    An enhanced stability characterization for aeroelastic energy harvesters is introduced by using both the normal form of the Hopf bifurcation and shooting method. Considering a triangular cylinder subjected to transverse galloping oscillations and a piezoelectric transducer to convert mechanical vibrations to electrical power, it is demonstrated that the nonlinear normal form is very beneficial to characterize the type of instability near bifurcation and determine the influence of structural and/or aerodynamic nonlinearities on the performance of the harvester. It is also shown that this tool is strong in terms of designing reliable aeroelastic energy harvesters. The results show that this technique can accurately predict the harvester's response only near bifurcation, however, cannot predict the stable solutions of the harvester when subcritical Hopf bifurcation takes place. To cover these drawbacks, the shooting method is employed. It turns out that this approach is beneficial in determining the stable and unstable solutions of the system and associated turning points. The results also show that the Floquet multipliers, obtained as the by-product of this method, can be used to characterize the response's type of the harvester. Thus, the normal form of the Hopf bifurcation and shooting method predictions can supplement each other to design stable and reliable aeroelastic energy harvesters.

  5. A shoe-embedded piezoelectric energy harvester for wearable sensors.

    Science.gov (United States)

    Zhao, Jingjing; You, Zheng

    2014-07-11

    Harvesting mechanical energy from human motion is an attractive approach for obtaining clean and sustainable electric energy to power wearable sensors, which are widely used for health monitoring, activity recognition, gait analysis and so on. This paper studies a piezoelectric energy harvester for the parasitic mechanical energy in shoes originated from human motion. The harvester is based on a specially designed sandwich structure with a thin thickness, which makes it readily compatible with a shoe. Besides, consideration is given to both high performance and excellent durability. The harvester provides an average output power of 1 mW during a walk at a frequency of roughly 1 Hz. Furthermore, a direct current (DC) power supply is built through integrating the harvester with a power management circuit. The DC power supply is tested by driving a simulated wireless transmitter, which can be activated once every 2-3 steps with an active period lasting 5 ms and a mean power of 50 mW. This work demonstrates the feasibility of applying piezoelectric energy harvesters to power wearable sensors.

  6. Low-frequency meandering piezoelectric vibration energy harvester.

    Science.gov (United States)

    Berdy, David F; Srisungsitthisunti, Pornsak; Jung, Byunghoo; Xu, Xianfan; Rhoads, Jeffrey F; Peroulis, Dimitrios

    2012-05-01

    The design, fabrication, and characterization of a novel low-frequency meandering piezoelectric vibration energy harvester is presented. The energy harvester is designed for sensor node applications where the node targets a width-to-length aspect ratio close to 1:1 while simultaneously achieving a low resonant frequency. The measured power output and normalized power density are 118 μW and 5.02 μW/mm(3)/g(2), respectively, when excited by an acceleration magnitude of 0.2 g at 49.7 Hz. The energy harvester consists of a laser-machined meandering PZT bimorph. Two methods, strain-matched electrode (SME) and strain-matched polarization (SMP), are utilized to mitigate the voltage cancellation caused by having both positive and negative strains in the piezoelectric layer during operation at the meander's first resonant frequency. We have performed finite element analysis and experimentally demonstrated a prototype harvester with a footprint of 27 x 23 mm and a height of 6.5 mm including the tip mass. The device achieves a low resonant frequency while maintaining a form factor suitable for sensor node applications. The meandering design enables energy harvesters to harvest energy from vibration sources with frequencies less than 100 Hz within a compact footprint.

  7. A Shoe-Embedded Piezoelectric Energy Harvester for Wearable Sensors

    Directory of Open Access Journals (Sweden)

    Jingjing Zhao

    2014-07-01

    Full Text Available Harvesting mechanical energy from human motion is an attractive approach for obtaining clean and sustainable electric energy to power wearable sensors, which are widely used for health monitoring, activity recognition, gait analysis and so on. This paper studies a piezoelectric energy harvester for the parasitic mechanical energy in shoes originated from human motion. The harvester is based on a specially designed sandwich structure with a thin thickness, which makes it readily compatible with a shoe. Besides, consideration is given to both high performance and excellent durability. The harvester provides an average output power of 1 mW during a walk at a frequency of roughly 1 Hz. Furthermore, a direct current (DC power supply is built through integrating the harvester with a power management circuit. The DC power supply is tested by driving a simulated wireless transmitter, which can be activated once every 2–3 steps with an active period lasting 5 ms and a mean power of 50 mW. This work demonstrates the feasibility of applying piezoelectric energy harvesters to power wearable sensors.

  8. An electromechanical finite element model for piezoelectric energy harvester plates

    Science.gov (United States)

    De Marqui Junior, Carlos; Erturk, Alper; Inman, Daniel J.

    2009-10-01

    Vibration-based energy harvesting has been investigated by several researchers over the last decade. The goal in this research field is to power small electronic components by converting the waste vibration energy available in their environment into electrical energy. Recent literature shows that piezoelectric transduction has received the most attention for vibration-to-electricity conversion. In practice, cantilevered beams and plates with piezoceramic layers are employed as piezoelectric energy harvesters. The existing piezoelectric energy harvester models are beam-type lumped parameter, approximate distributed parameter and analytical distributed parameter solutions. However, aspect ratios of piezoelectric energy harvesters in several cases are plate-like and predicting the power output to general (symmetric and asymmetric) excitations requires a plate-type formulation which has not been covered in the energy harvesting literature. In this paper, an electromechanically coupled finite element (FE) plate model is presented for predicting the electrical power output of piezoelectric energy harvester plates. Generalized Hamilton's principle for electroelastic bodies is reviewed and the FE model is derived based on the Kirchhoff plate assumptions as typical piezoelectric energy harvesters are thin structures. Presence of conductive electrodes is taken into account in the FE model. The predictions of the FE model are verified against the analytical solution for a unimorph cantilever and then against the experimental and analytical results of a bimorph cantilever with a tip mass reported in the literature. Finally, an optimization problem is solved where the aluminum wing spar of an unmanned air vehicle (UAV) is modified to obtain a generator spar by embedding piezoceramics for the maximum electrical power without exceeding a prescribed mass addition limit.

  9. Multiphysics Simulation in the Development of Thermoelectric Energy Harvesting Systems

    Science.gov (United States)

    Nesarajah, Marco; Frey, Georg

    2016-03-01

    This contribution presents a model-based development process for thermoelectric energy harvesting systems. Such systems convert thermal energy into electrical energy and produce enough energy to supply low-power devices. Realizations require three main challenges to be solved: to guarantee optimal thermal connection of the thermoelectric generators, to find a good design for the energy harvesting system, and to find an optimal electrical connection. Therefore, a development process is presented here. The process is divided into different steps and supports the developer in finding an optimal thermoelectric energy harvesting system for a given heat source and given objectives (technical and economical). During the process, several steps are supported by simulation models. Based on developed model libraries in Modelica®/Dymola®, thermal, thermoelectrical, electrical, and control components can be modeled, integrated into different variants, and verified step by step before the system is physically built and finally validated. The process is illustrated by an example through all the steps.

  10. Implementation of a piezoelectric energy harvester in railway health monitoring

    Science.gov (United States)

    Li, Jingcheng; Jang, Shinae; Tang, Jiong

    2014-03-01

    With development of wireless sensor technology, wireless sensor network has shown a great potential for railway health monitoring. However, how to supply continuous power to the wireless sensor nodes is one of the critical issues in long-term full-scale deployment of the wireless smart sensors. Some energy harvesting methodologies have been available including solar, vibration, wind, etc; among them, vibration-based energy harvester using piezoelectric material showed the potential for converting ambient vibration energy to electric energy in railway health monitoring even for underground subway systems. However, the piezoelectric energy harvester has two major problems including that it could only generate small amount of energy, and that it should match the exact narrow band natural frequency with the excitation frequency. To overcome these problems, a wide band piezoelectric energy harvester, which could generate more power on various frequencies regions, has been designed and validated with experimental test. Then it was applied to a full-scale field test using actual railway train. The power generation of the wide band piezoelectric array has been compared to a narrow-band, resonant-based, piezoelectric energy harvester.

  11. Energy harvesting potential of tuned inertial mass electromagnetic transducers

    Science.gov (United States)

    Asai, Takehiko; Araki, Yoshikazu; Ikago, Kohju

    2017-02-01

    The demand for developing renewable energy technologies has been growing in today's society. As one of promising renewable energy sources, large-scale energy harvesting from structural vibrations employing electromagnetic transducers has recently been proposed and considerable effort has been devoted to increase the power generation capability. In this paper, we introduce the mechanism of a tuned inertial mass electromagnetic transducer (TIMET), which can absorb vibratory energy more efficiently by tuning the parameters to adjust the system. Then we propose a new vibratory energy harvester with the TIMET and determine the parameter values for the device with a simple static admittance (SA) control law to maximize the energy harvested from a stationary stochastic disturbance. To investigate the energy harvesting potential of the TIMET further, the performance-guaranteed (PG) control and the LQG control proposed in the literature are applied as well. Then the numerical simulation studies are carried out and the effectiveness of the proposed energy harvester is examined by comparing the traditional electromagnetic transducers.

  12. An Energy Aware Adaptive Sampling Algorithm for Energy Harvesting WSN with Energy Hungry Sensors.

    Science.gov (United States)

    Srbinovski, Bruno; Magno, Michele; Edwards-Murphy, Fiona; Pakrashi, Vikram; Popovici, Emanuel

    2016-03-28

    Wireless sensor nodes have a limited power budget, though they are often expected to be functional in the field once deployed for extended periods of time. Therefore, minimization of energy consumption and energy harvesting technology in Wireless Sensor Networks (WSN) are key tools for maximizing network lifetime, and achieving self-sustainability. This paper proposes an energy aware Adaptive Sampling Algorithm (ASA) for WSN with power hungry sensors and harvesting capabilities, an energy management technique that can be implemented on any WSN platform with enough processing power to execute the proposed algorithm. An existing state-of-the-art ASA developed for wireless sensor networks with power hungry sensors is optimized and enhanced to adapt the sampling frequency according to the available energy of the node. The proposed algorithm is evaluated using two in-field testbeds that are supplied by two different energy harvesting sources (solar and wind). Simulation and comparison between the state-of-the-art ASA and the proposed energy aware ASA (EASA) in terms of energy durability are carried out using in-field measured harvested energy (using both wind and solar sources) and power hungry sensors (ultrasonic wind sensor and gas sensors). The simulation results demonstrate that using ASA in combination with an energy aware function on the nodes can drastically increase the lifetime of a WSN node and enable self-sustainability. In fact, the proposed EASA in conjunction with energy harvesting capability can lead towards perpetual WSN operation and significantly outperform the state-of-the-art ASA.

  13. Modeling of a nanoscale flexoelectric energy harvester with surface effects

    Science.gov (United States)

    Yan, Zhi

    2017-04-01

    This work presents the modeling of a beam energy harvester scavenging energy from ambient vibration based on the phenomenon of flexoelectricity. By considering surface elasticity, residual surface stress, surface piezoelectricity and bulk flexoelectricity, a modified Euler-Bernoulli beam model for the energy harvester is developed. After deriving the requisite energy expressions, the extended Hamilton's principle and the assumed-modes method are employed to obtain the discrete electromechanical Euler-Lagrange's equations. Then, the expressions of the steady-state electromechanical responses are given for harmonic base excitation. Numerical simulations are conducted to show the output voltage and the output power of the flexoelectric energy harvesters with different materials and sizes. Particular emphasis is given to the surface effects on the performance of the energy harvesters. It is found that the surface effects are sensitive to the beam geometries and the surface material constants, and the effect of residual surface stress is more significant than that of the surface elasticity and the surface piezoelectricity. The axial deformation of the beam is also considered in the model to account for the electromechanical coupling due to piezoelectricity, and results indicate that piezoelectricity will diminish the output electrical quantities for the case investigated. This work could lead to the development of flexoelectric energy harvesters that can make the micro- and nanoscale sensor systems autonomous.

  14. Harvesting Energy from the Counterbalancing (Weaving Movement in Bicycle Riding

    Directory of Open Access Journals (Sweden)

    Shashank Priya

    2012-07-01

    Full Text Available Bicycles are known to be rich source of kinetic energy, some of which is available for harvesting during speedy and balanced maneuvers by the user. A conventional dynamo attached to the rim can generate a large amount of output power at an expense of extra energy input from the user. However, when applying energy conversion technology to human powered equipments, it is important to minimize the increase in extra muscular activity and to maximize the efficiency of human movements. This study proposes a novel energy harvesting methodology that utilizes lateral oscillation of bicycle frame (weaving caused by user weight shifting movements in order to increase the pedaling force in uphill riding or during quick speed-up. Based on the 3D motion analysis, we designed and implemented the prototype of an electro-dynamic energy harvester that can be mounted on the bicycle’s handlebar to collect energy from the side-to-side movement. The harvester was found to generate substantial electric output power of 6.6 mW from normal road riding. It was able to generate power even during uphill riding which has never been shown with other approaches. Moreover, harvesting of energy from weaving motion seems to increase the economy of cycling by helping efficient usage of human power.

  15. Harvesting energy from the counterbalancing (weaving) movement in bicycle riding.

    Science.gov (United States)

    Yang, Yoonseok; Yeo, Jeongjin; Priya, Shashank

    2012-01-01

    Bicycles are known to be rich source of kinetic energy, some of which is available for harvesting during speedy and balanced maneuvers by the user. A conventional dynamo attached to the rim can generate a large amount of output power at an expense of extra energy input from the user. However, when applying energy conversion technology to human powered equipments, it is important to minimize the increase in extra muscular activity and to maximize the efficiency of human movements. This study proposes a novel energy harvesting methodology that utilizes lateral oscillation of bicycle frame (weaving) caused by user weight shifting movements in order to increase the pedaling force in uphill riding or during quick speed-up. Based on the 3D motion analysis, we designed and implemented the prototype of an electro-dynamic energy harvester that can be mounted on the bicycle's handlebar to collect energy from the side-to-side movement. The harvester was found to generate substantial electric output power of 6.6 mW from normal road riding. It was able to generate power even during uphill riding which has never been shown with other approaches. Moreover, harvesting of energy from weaving motion seems to increase the economy of cycling by helping efficient usage of human power.

  16. Intermittent energy harvesting improves the performance of microbial fuel cells.

    Science.gov (United States)

    Dewan, Alim; Beyenal, Haluk; Lewandowski, Zbigniew

    2009-06-15

    In this study, we compare the efficiencies of harvesting energy from microbial fuel cells (MFC) using two modes of operation: (1) continuous-passing the current through an electrical load-and (2) intermittent-first accumulating the energy in a capacitor and then discharging it through the load. Each of these two modes of operation has advantages and disadvantages: the first mode of operation allows the continuous powering of low-power-consuming devices, and the second mode of operation allows the intermittent powering of high-power-consuming devices. We used a two-compartment MFC: in the anodic compartment, Shewanella oneidensis MR-1 was grown using lactate as an electron donor, whereas in the cathodic compartment we used an electrode made of manganese-based catalyzed carbon bonded to a current-collecting screen made of platinum mesh and oxygen as the electron acceptor. The maximum power generated by harvesting energy intermittently was 152 microW, which is 111% higher than the 72 microW generated by harvesting the energy continuously. We conclude that in the operation of MFCs it is beneficial to harvest the energy intermittently. This not only allows the powering of external devices of high power consumption but also allows generating power with greater energy efficiency than does harvesting the energy continuously.

  17. Thermoelectric Energy Harvesting from Transient Ambient Temperature Gradients

    Science.gov (United States)

    Moser, André; Erd, Metin; Kostic, Milos; Cobry, Keith; Kroener, Michael; Woias, Peter

    2012-06-01

    We examine a thermoelectric harvester that converts electrical energy from the naturally occurring temperature difference between ambient air and large thermal storage capacitors such as building walls or the soil. For maximum power output, the harvester design is implemented in two steps: source matching of the thermal and electrical interfaces to the energy source (system level) followed by load matching of the generator to these interfaces (subsystem level). Therefore, we measure thermal source properties such as the temperature difference, the air velocity, and the cutoff frequency in two application scenarios (road tunnel and office building). We extend a stationary model of the harvester into the time domain to account for transient behavior of the source. Based on the model and the source measurements, we perform the source and load matching. The resulting harvester consists of a pin fin heat sink with a thermal resistance of 6.2 K/W and a cutoff frequency 2.5 times greater than that of the source, a thermoelectric generator, and a DC/DC step-up converter starting at a total temperature difference of only Δ T = 1.2 K. In a final road tunnel field test, this optimized harvester converts 70 mJ of electrical energy per day without any direct solar irradiation. The energy provided by the harvester enables 415 data transmissions from a wireless sensor node per day.

  18. Wireless energy transmission to supplement energy harvesters in sensor network applications

    Energy Technology Data Exchange (ETDEWEB)

    Farinholt, Kevin M [Los Alamos National Laboratory; Taylor, Stuart G [Los Alamos National Laboratory; Park, Gyuhae [Los Alamos National Laboratory; Farrar, Charles R [Los Alamos National Laboratory

    2010-01-01

    In this paper we present a method for coupling wireless energy transmission with traditional energy harvesting techniques in order to power sensor nodes for structural health monitoring applications. The goal of this study is to develop a system that can be permanently embedded within civil structures without the need for on-board power sources. Wireless energy transmission is included to supplement energy harvesting techniques that rely on ambient or environmental, energy sources. This approach combines several transducer types that harvest ambient energy with wireless transmission sources, providing a robust solution that does not rely on a single energy source. Experimental results from laboratory and field experiments are presented to address duty cycle limitations of conventional energy harvesting techniques, and the advantages gained by incorporating a wireless energy transmission subsystem. Methods of increasing the efficiency, energy storage medium, target applications and the integrated use of energy harvesting sources with wireless energy transmission will be discussed.

  19. MIMO Precoding for Networked Control Systems with Energy Harvesting Sensors

    Science.gov (United States)

    Cai, Songfu; Lau, Vincent K. N.

    2016-09-01

    In this paper, we consider a MIMO networked control system with an energy harvesting sensor, where an unstable MIMO dynamic system is connected to a controller via a MIMO fading channel. We focus on the energy harvesting and MIMO precoding design at the sensor so as to stabilize the unstable MIMO dynamic plant subject to the energy availability constraint at the sensor. Using the Lyapunov optimization approach, we propose a closed-form dynamic energy harvesting and dynamic MIMO precoding solution, which has an event-driven control structure. Furthermore, the MIMO precoding solution is shown to have an eigenvalue water-filling structure, where the water level depends on the state estimation covariance, energy queue and the channel state, and the sea bed level depends on the state estimation covariance. The proposed scheme is also compared with various baselines and we show that significant performance gains can be achieved.

  20. Optical arc sensor using energy harvesting power source

    Science.gov (United States)

    Choi, Kyoo Nam; Rho, Hee Hyuk

    2016-06-01

    Wireless sensors without external power supply gained considerable attention due to convenience both in installation and operation. Optical arc detecting sensor equipping with self sustaining power supply using energy harvesting method was investigated. Continuous energy harvesting method was attempted using thermoelectric generator to supply standby power in micro ampere scale and operating power in mA scale. Peltier module with heat-sink was used for high efficiency electricity generator. Optical arc detecting sensor with hybrid filter showed insensitivity to fluorescent and incandescent lamps under simulated distribution panel condition. Signal processing using integrating function showed selective arc discharge detection capability to different arc energy levels, with a resolution below 17J energy difference, unaffected by bursting arc waveform. The sensor showed possibility for application to arc discharge detecting sensor in power distribution panel. Also experiment with proposed continuous energy harvesting method using thermoelectric power showed possibility as a self sustainable power source of remote sensor.

  1. Practical energy harvesting for microbial fuel cells: a review.

    Science.gov (United States)

    Wang, Heming; Park, Jae-Do; Ren, Zhiyong Jason

    2015-03-17

    The microbial fuel cell (MFC) technology offers sustainable solutions for distributed power systems and energy positive wastewater treatment, but the generation of practically usable power from MFCs remains a major challenge for system scale up and application. Commonly used external resistors will not harvest any usable energy, so energy-harvesting circuits are needed for real world applications. This review summarizes, explains, and discusses the different energy harvesting methods, components, and systems that can extract and condition the MFC energy for direct utilization. This study aims to assist environmental scientists and engineers to gain fundamental understandings of these electronic systems and algorithms, and it also offers research directions and insights on how to overcome the barriers, so the technology can be further advanced and applied in larger scale.

  2. Magnetostrictive-piezoelectric composite structures for energy harvesting

    Science.gov (United States)

    Lafont, Thomas; Gimeno, L.; Delamare, J.; Lebedev, G. A.; Zakharov, D. I.; Viala, B.; Cugat, O.; Galopin, N.; Garbuio, L.; Geoffroy, O.

    2012-09-01

    In this paper, harvesters coupling magnetostrictive and piezoelectric materials are investigated. The energy conversion of quasi-static magnetic field variations into electricity is detailed. Experimental results are exposed for two macroscopic demonstrators based on the rotation of a permanent magnet. These composite/hybrid devices use both piezoelectric and magnetostrictive (amorphous FeSiB ribbon or bulk Terfenol-D) materials. A quasi-static (or ultra-low frequency) harvester is constructed with exploitable output voltage, even in quasi-static mode. Integrated micro-harvesters using sub-micron multilayers of active materials on Si have been built and are currently being characterized.

  3. Energy harvesting: an integrated view of materials, devices and applications.

    Science.gov (United States)

    Radousky, H B; Liang, H

    2012-12-21

    Energy harvesting refers to the set of processes by which useful energy is captured from waste, environmental, or mechanical sources and is converted into a usable form. The discipline of energy harvesting is a broad topic that includes established methods and materials such as photovoltaics and thermoelectrics, as well as more recent technologies that convert mechanical energy, magnetic energy and waste heat to electricity. This article will review various state-of-the-art materials and devices for direct energy conversion and in particular will include multistep energy conversion approaches. The article will highlight the nano-materials science underlying energy harvesting principles and devices, but also include more traditional bulk processes and devices as appropriate and synergistic. Emphasis is placed on device-design innovations that lead to higher efficiency energy harvesting or conversion technologies ranging from the cm/mm-scale down to MEMS/NEMS (micro- and nano-electromechanical systems) devices. Theoretical studies are reviewed, which address transport properties, crystal chemistry, thermodynamic analysis, energy transfer, system efficiency and device operation. New developments in experimental methods; device design and fabrication; nanostructured materials fabrication; materials properties; and device performance measurement techniques are discussed.

  4. Energy Harvesting for Structural Health Monitoring Sensor Networks

    Energy Technology Data Exchange (ETDEWEB)

    Park, G.; Farrar, C. R.; Todd, M. D.; Hodgkiss, T.; Rosing, T.

    2007-02-26

    This report has been developed based on information exchanges at a 2.5-day workshop on energy harvesting for embedded structural health monitoring (SHM) sensing systems that was held June 28-30, 2005, at Los Alamos National Laboratory. The workshop was hosted by the LANL/UCSD Engineering Institute (EI). This Institute is an education- and research-focused collaboration between Los Alamos National Laboratory (LANL) and the University of California, San Diego (UCSD), Jacobs School of Engineering. A Statistical Pattern Recognition paradigm for SHM is first presented and the concept of energy harvesting for embedded sensing systems is addressed with respect to the data acquisition portion of this paradigm. Next, various existing and emerging sensing modalities used for SHM and their respective power requirements are summarized, followed by a discussion of SHM sensor network paradigms, power requirements for these networks and power optimization strategies. Various approaches to energy harvesting and energy storage are discussed and limitations associated with the current technology are addressed. This discussion also addresses current energy harvesting applications and system integration issues. The report concludes by defining some future research directions and possible technology demonstrations that are aimed at transitioning the concept of energy harvesting for embedded SHM sensing systems from laboratory research to field-deployed engineering prototypes.

  5. CMOS indoor light energy harvesting system for wireless sensing applications

    CERN Document Server

    Ferreira Carvalho, Carlos Manuel

    2016-01-01

    This book discusses in detail the CMOS implementation of energy harvesting.  The authors describe an integrated, indoor light energy harvesting system, based on a controller circuit that dynamically and automatically adjusts its operation to meet the actual light circumstances of the environment where the system is placed.  The system is intended to power a sensor node, enabling an autonomous wireless sensor network (WSN). Although designed to cope with indoor light levels, the system is also able to work with higher levels, making it an all-round light energy harvesting system.  The discussion includes experimental data obtained from an integrated manufactured prototype, which in conjunction with a photovoltaic (PV) cell, serves as a proof of concept of the desired energy harvesting system.  ·         Discusses several energy sources which can be used to power energy harvesting systems and includes an overview of PV cell technologies  ·         Includes an introduction to voltage step-...

  6. Feasibility study of thermal energy harvesting using lead free pyroelectrics

    Science.gov (United States)

    Karim, Hasanul; Sarker, Md Rashedul H.; Shahriar, Shaimum; Arif Ishtiaque Shuvo, Mohammad; Delfin, Diego; Hodges, Deidra; (Bill Tseng, Tzu-Liang; Roberson, David; Love, Norman; Lin, Yirong

    2016-05-01

    Energy harvesting has significant potential for applications in energizing wireless sensors and charging energy storage devices. To date, one of the most widely investigated materials for mechanical and thermal energy harvesting is lead zirconate titanate (PZT). However, lead has detrimental effects on the environment and on health. Hence, alternative materials are required for this purpose. In this paper, a lead free material, lithium niobate (LNB) is investigated as a potential material for pyroelectric energy harvesting. Although its theoretical pyroelectric properties are lower compared to PZT, it has better properties than other lead free alternatives such as ZnO. In addition, LNB has a high Curie temperature of about 1142 °C, which makes it applicable for high temperature energy harvesting, where other pyroelectric ceramics are not suitable. Herein, an energy harvesting and storage system composed of a single crystal LNB and a porous carbon-based super-capacitor was investigated. It is found that with controlled heating and cooling, a single wafer of LNB (75 mm diameter and 0.5 mm thickness) could generate 437.72 nW cm-3 of power and it could be used to charge a super-capacitor with a charging rate of 2.63 mV (h cm3)-1.

  7. Throughput of Wireless Networks Powered by Energy Harvesting

    CERN Document Server

    Huang, Kaibin

    2011-01-01

    Designing mobile devices for harvesting ambient energy such as kinetic activities or electromagnetic radiation (EMR) will enable mobile networks to self sustain besides alleviate global warming. The throughput of a mobile ad hoc network powered by energy harvesting is analyzed in this paper using a stochastic-geometry approach. The transmitters powered by energy harvesting are modeled as a Poisson point process (PPP); each transmits to a receiver at an unit distance using either a random-access protocol or the time-hopping multiple access (THMA) and satisfying an outage-probability constraint. Consider non-EMR energy harvesting where energy packets of random sizes arrive at a transmitter following a stationary random process. By applying Mapping Theorem, the network (spatial) throughput for random access and in the limit of a long harvesting interval is derived in simple closed-form functions of the energy-arrival rate, transmitter density and coding rate. These results show that the throughput of a sparse ne...

  8. Development of an Energy Harvesting Device using Piezoceramic Materials

    Science.gov (United States)

    Kulkarni, Vainatey

    Piezoelectric energy harvesters are increasingly being pursued for their potential to replace finite-life batteries in wireless sensor modules and for their potential to create self-powered devices. This work presents the development of a novel piezoelectric harvester that attempts to improve upon the power output limitations of current piezoelectric harvesting technology. This novel harvester uses the concept of torsion on a tube to produce shear stresses and hence uses improved piezoelectric properties of the shear mode of piezoceramics to generate higher power outputs. This concept is first presented in this work and a proof-of-concept prototype is utilized to experimentally demonstrate the validity of this novel device. After this, the behaviour of the novel harvester is explored through an investigation into three cross-section geometries of the torsion tube and varying geometries of the eccentric mass using three different comparison metrics. Through this, it is observed that configurations with higher torsional compliance and high eccentric mass inertias have the potential for the highest power output and highest harvester effectiveness. However, the mechanical damping in the system is also found to significantly impact the harvester output resulting in prototypes of the various configurations not performing as expected. As a result of this discrepancy, the factors affecting the performance of the harvester are analyzed in greater detail through the development of a mathematical model that is then used to develop a set of guidelines to direct the design of a torsion harvester for a desired application. These guidelines are then used to develop an improved torsion harvester with a demonstrated ability to produce 1.2 mW of output power at its resonant frequency to power a wireless sensor module. Finally, the use of alternative materials such as single crystals of PMN-PT in the torsion harvester is also examined. Through finite element simulations and with

  9. Finite element analysis of hybrid energy harvesting of piezoelectric and electromagnetic

    OpenAIRE

    Muhammad Yazid Muhammad Ammar Faris; Jamil Norlida; Muhmed Razali Nik Nurul Husna; Yusoff Ahmad Razlan

    2017-01-01

    Harvesting energy from ambient vibrations is a highly required method because of the wide range of available sources that produce vibration energy application from industrial machinery to human motion application. In this paper, the implementation of harvesting energy from two technologies to form a hybrid energy harvester system was analyzed. These two technologies involve the piezoelectric harvesting energy and the electromagnetic harvesting energy. A finite element model was developed usin...

  10. Human-motion energy harvester for autonomous body area sensors

    Science.gov (United States)

    Geisler, M.; Boisseau, S.; Perez, M.; Gasnier, P.; Willemin, J.; Ait-Ali, I.; Perraud, S.

    2017-03-01

    This paper reports on a method to optimize an electromagnetic energy harvester converting the low-frequency body motion and aimed at powering wireless body area sensors. This method is based on recorded accelerations, and mechanical and transduction models that enable an efficient joint optimization of the structural parameters. An optimized prototype of 14.8 mmØ × 52 mm, weighting 20 g, has generated up to 4.95 mW in a resistive load when worn at the arm during a run, and 6.57 mW when hand-shaken. Among the inertial electromagnetic energy harvesters reported so far, this one exhibits one of the highest power densities (up to 730 μW cm‑3). The energy harvester was finally used to power a bluetooth low energy wireless sensor node with accelerations measurements at 25 Hz.

  11. Electromagnetic Vibration Energy Harvesting Devices Architectures, Design, Modeling and Optimization

    CERN Document Server

    Spreemann, Dirk

    2012-01-01

    Electromagnetic vibration transducers are seen as an effective way of harvesting ambient energy for the supply of sensor monitoring systems. Different electromagnetic coupling architectures have been employed but no comprehensive comparison with respect to their output performance has been carried out up to now. Electromagnetic Vibration Energy Harvesting Devices introduces an optimization approach which is applied to determine optimal dimensions of the components (magnet, coil and back iron). Eight different commonly applied coupling architectures are investigated. The results show that correct dimensions are of great significance for maximizing the efficiency of the energy conversion. A comparison yields the architectures with the best output performance capability which should be preferably employed in applications. A prototype development is used to demonstrate how the optimization calculations can be integrated into the design–flow. Electromagnetic Vibration Energy Harvesting Devices targets the design...

  12. Passively Self-Tuning Piezoelectric Energy Harvesting System

    Science.gov (United States)

    Gregg, C. G.; Pillatsch, P.; Wright, P. K.

    2014-11-01

    Real world systems that are candidates for vibrational energy harvesting rarely vibrate at a single frequency, nor are these frequencies constant over time. This necessitates that vibration harvesters operate over a wide bandwidth or tune their resonance. Most tunable devices require additional energy or active control to achieve resonance over various frequencies. This work presents a passively self-tuning energy harvester that autonomously adapts its resonant frequency to the input without requiring additional energy. The system consists of a clamped- clamped beam, a movable proof mass, and a piezoelectric patch bonded to the underside of the beam. It demonstrated an open-circuit voltage output of 668 mVrms at 160Hz, 0.65g input excitation. Discrepancies between displacement and voltage magnification factors upon tuning at higher frequencies are discussed, as well as instabilities of the system and sensitivity to proof mass characteristics.

  13. Cooperative energy harvesting-adaptive MAC protocol for WBANs.

    Science.gov (United States)

    Esteves, Volker; Antonopoulos, Angelos; Kartsakli, Elli; Puig-Vidal, Manel; Miribel-Català, Pere; Verikoukis, Christos

    2015-05-28

    In this paper, we introduce a cooperative medium access control (MAC) protocol, named cooperative energy harvesting (CEH)-MAC, that adapts its operation to the energy harvesting (EH) conditions in wireless body area networks (WBANs). In particular, the proposed protocol exploits the EH information in order to set an idle time that allows the relay nodes to charge their batteries and complete the cooperation phase successfully. Extensive simulations have shown that CEH-MAC significantly improves the network performance in terms of throughput, delay and energy efficiency compared to the cooperative operation of the baseline IEEE 802.15.6 standard.

  14. Analytical simulation of the cantilever-type energy harvester

    Directory of Open Access Journals (Sweden)

    Jie Mei

    2016-01-01

    Full Text Available This article describes an analytical model of the cantilever-type energy harvester based on Euler–Bernoulli’s beam theory. Starting from the Hamiltonian form of total energy equation, the bending mode shapes and electromechanical dynamic equations are derived. By solving the constitutive electromechanical dynamic equation, the frequency transfer function of output voltage and power can be obtained. Through a case study of a unimorph piezoelectric energy harvester, this analytical modeling method has been validated by the finite element method.

  15. Nonlinear metamaterials for electromagnetic energy harvesting (Conference Presentation)

    Science.gov (United States)

    Oumbe Tekam, Gabin Thibaut; Ginis, Vincent; Seetharamdoo, Divitha; Danckaert, Jan

    2016-09-01

    Surrounded by electromagnetic radiation coming from wireless power transfer to consumer devices such as mobile phones, computers and television, our society is facing the scientific and technological challenge to recover energy that is otherwise lost to the environment. Energy harvesting is an emerging field of research focused on this largely unsolved problem, especially in the microwave regime. Metamaterials provide a very promising platform to meet this purpose. These artificial materials are made from subwavelength building blocks, and can be designed by resonate at particular frequencies, depending on their shape, geometry, size, and orientation. In this work, we show that an efficient electromagnetic energy harvester can be design by inserting a nonlinear element directly within the metamaterial unit cell, leading to the conversion of RF input power to DC charge accumulation. The electromagnetic energy harvester operating at microwave frequencies is built from a cut-wire metasurface, which operates as a quasistatic electric dipole resonator. Using the equivalent electrical circuit, we design the parameters to tune the resonance frequency of the harvester at the desired frequency, and we compare these results with numerical simulations. Finally, we discuss the efficiency of our metamaterial energy harvesters. This work potentially offers a variety of applications, for example in the telecommunications industry to charge phones, in robotics to power microrobots, and also in medicine to advance pacemakers or health monitoring sensors.

  16. Magnetic flux concentration methods for magnetic energy harvesting module

    Directory of Open Access Journals (Sweden)

    Wakiwaka Hiroyuki

    2013-01-01

    Full Text Available This paper presents magnetic flux concentration methods for magnetic energy harvesting module. The purpose of this study is to harvest 1 mW energy with a Brooks coil 2 cm in diameter from environmental magnetic field at 60 Hz. Because the harvesting power is proportional to the square of the magnetic flux density, we consider the use of a magnetic flux concentration coil and a magnetic core. The magnetic flux concentration coil consists of an air­core Brooks coil and a resonant capacitor. When a uniform magnetic field crossed the coil, the magnetic flux distribution around the coil was changed. It is found that the magnetic field in an area is concentrated larger than 20 times compared with the uniform magnetic field. Compared with the air­core coil, our designed magnetic core makes the harvested energy ten­fold. According to ICNIRP2010 guideline, the acceptable level of magnetic field is 0.2 mT in the frequency range between 25 Hz and 400 Hz. Without the two magnetic flux concentration methods, the corresponding energy is limited to 1 µW. In contrast, our experimental results successfully demonstrate energy harvesting of 1 mW from a magnetic field of 0.03 mT at 60 Hz.

  17. A nonlinear piezoelectric energy harvester for various mechanical motions

    Energy Technology Data Exchange (ETDEWEB)

    Fan, Kangqi, E-mail: kangqifan@gmail.com [School of Mechano-Electronic Engineering, Xidian University, Xi' an 710071 (China); Department of Electrical and Computer Engineering, University of Alberta, Edmonton T6G 2V4 (Canada); Chang, Jianwei; Liu, Zhaohui; Zhu, Yingmin [School of Mechano-Electronic Engineering, Xidian University, Xi' an 710071 (China); Pedrycz, Witold [Department of Electrical and Computer Engineering, University of Alberta, Edmonton T6G 2V4 (Canada)

    2015-06-01

    This study presents a nonlinear piezoelectric energy harvester with intent to scavenge energy from diverse mechanical motions. The harvester consists of four piezoelectric cantilever beams, a cylindrical track, and a ferromagnetic ball, with magnets integrated to introduce the magnetic coupling between the ball and the beams. The experimental results demonstrate that the harvester is able to collect energy from various directions of vibrations. For the vibrations perpendicular to the ground, the maximum peak voltage is increased by 3.2 V and the bandwidth of the voltage above 4 V is increased by more than 4 Hz compared to the results obtained when using a conventional design. For the vibrations along the horizontal direction, the frequency up-conversion is realized through the magnetic coupling. Moreover, the proposed design can harvest energy from the sway motion around different directions on the horizontal plane. Harvesting energy from the rotation motion is also achieved with an operating bandwidth of approximately 6 Hz.

  18. A MEMS Energy Harvesting Device for Vibration with Low Acceleration

    DEFF Research Database (Denmark)

    Triches, Marco; Wang, Fei; Crovetto, Andrea

    2012-01-01

    We propose a polymer electret based energy harvesting device in order to extract energy from vibration sources with low acceleration. With MEMS technology, a silicon structure is fabricated which can resonate in 2D directions. Thanks to the excellent mechanical properties of the silicon material...

  19. Security challenges for energy-harvesting wireless sensor networks

    DEFF Research Database (Denmark)

    Di Mauro, Alessio; Papini, Davide; Dragoni, Nicola

    2012-01-01

    With the recent introduction of Energy-Harvesting nodes, security is gaining more and more importance in sensor networks. By exploiting the ability of scavenging energy from the surrounding environment, the lifespan of a node has drastically increased. This is one of the reason why security needs...... networks. Finally, we present and discuss existing security solutions for EH-WSNs....

  20. Macro and Micro Scale Electromagnetic Kinetic Energy Harvesting Generators

    CERN Document Server

    Beeby, S -P; Torah, R -N; Koukharenko, E; Roberts, S; O'Donnell, T; Roy, S

    2007-01-01

    This paper is concerned with generators that harvest electrical energy from the kinetic energy present in the sensor nodes environment. These generators have the potential to replace or augment battery power which has a limited lifetime and requires periodic replacement which limits the placement and application of the sensor node.

  1. Harvesting

    Science.gov (United States)

    Since the introduction of the first successful mechanical harvester, mechanized cotton harvest has continued to decrease the cost and man hours required to produce a bale of cotton. Cotton harvesting in the US is completely mechanized and is accomplished by two primary machines, the spindle picker a...

  2. Advanced Energy Harvesting Control Schemes for Marine Renewable Energy Devices

    Energy Technology Data Exchange (ETDEWEB)

    McEntee, Jarlath [Ocean Renewable Power Company, Portland, ME (United States); Polagye, Brian [Ocean Renewable Power Company, Portland, ME (United States); Fabien, Brian [Ocean Renewable Power Company, Portland, ME (United States); Thomson, Jim [Ocean Renewable Power Company, Portland, ME (United States); Kilcher, Levi [Ocean Renewable Power Company, Portland, ME (United States); Marnagh, Cian [Ocean Renewable Power Company, Portland, ME (United States); Donegan, James [Ocean Renewable Power Company, Portland, ME (United States)

    2016-03-31

    The Advanced Energy Harvesting Control Schemes for Marine Renewable Energy Devices (Project) investigated, analyzed and modeled advanced turbine control schemes with the objective of increasing the energy harvested by hydrokinetic turbines in turbulent flow. Ocean Renewable Power Company (ORPC) implemented and validated a feedforward controller to increase power capture; and applied and tested the controls on ORPC’s RivGen® Power Systems in Igiugig, Alaska. Assessments of performance improvements were made for the RivGen® in the Igiugig environment and for ORPC’s TidGen® Power System in a reference tidal environment. Annualized Energy Production (AEP) and Levelized Cost of Energy (LCOE) improvements associated with implementation of the recommended control methodology were made for the TidGen® Power System in the DOE reference tidal environment. System Performance Advancement (SPA) goals were selected for the project. SPA targets were to improve Power to Weight Ratio (PWR) and system Availability, with the intention of reducing Levelized Cost of Electricity (LCOE). This project focused primarily reducing in PWR. Reductions in PWR of 25.5% were achieved. Reductions of 20.3% in LCOE were achieved. This project evaluated four types of controllers which were tested in simulation, emulation, a laboratory flume, and the field. The adaptive Kω2 controller performs similarly to the non-adaptive version of the same controller and may be useful in tidal channels where the mean velocity is continually evolving. Trends in simulation were largely verified through experiments, which also provided the opportunity to test assumptions about turbine responsiveness and control resilience to varying scales of turbulence. Laboratory experiments provided an essential stepping stone between simulation and implementation on a field-scale turbine. Experiments also demonstrated that using “energy loss” as a metric to differentiate between well-designed controllers operating at

  3. All-Elastomer-Based Triboelectric Nanogenerator as a Keyboard Cover To Harvest Typing Energy.

    Science.gov (United States)

    Li, Shengming; Peng, Wenbo; Wang, Jie; Lin, Long; Zi, Yunlong; Zhang, Gong; Wang, Zhong Lin

    2016-08-23

    The drastic expansion of consumer electronics (like personal computers, touch pads, smart phones, etc.) creates many human-machine interfaces and multiple types of interactions between human and electronics. Considering the high frequency of such operations in our daily life, an extraordinary amount of biomechanical energy from typing or pressing buttons is available. In this study, we have demonstrated a highly flexible triboelectric nanogenerator (TENG) solely made from elastomeric materials as a cover on a conventional keyboard to harvest biomechanical energy from typing. A dual-mode working mechanism is established with a high transferred charge density of ∼140 μC/m(2) due to both structural and material innovations. We have also carried out fundamental investigations of its performance dependence on various structural factors for optimizing the electric output in practice. The fully packaged keyboard-shaped TENG is further integrated with a horn-like polypyrrole-based supercapacitor as a self-powered system. Typing in normal speed for 1 h, ∼8 × 10(-4) J electricity could be stored, which is capable of driving an electronic thermometer/hydrometer. Our keyboard cover also performs outstanding long-term stability, water resistance, as well as insensitivity to surface conditions, and the last feature makes it useful to research the typing behaviors of different people.

  4. Uncertainty Quantification of Piezoelectric Energy Harvesters from Aeroelastic Vibrations

    Directory of Open Access Journals (Sweden)

    Abdelkefi Abdessattar

    2012-07-01

    Full Text Available A stochastic approach is presented to evaluate the uncertainties associated with variations in design parameters of a piezoaeroelastic energy harvester. The sensitivities of the harvested power to variations in the load resistance, the eccentricity (distance between the center of mass and the elastic axis, and the nonlinear coeffcients are also determined. Moreover, the non-intrusive formulation of the polynomial chaos expansion in terms of the multivariate Hermite polynomials was employed to quantify the sensitivities in the harvested power and the plunge and pitch motions. The results show that the relationship between the input parameters and the harvested power is highly nonlinear. The results show also that the generated power is most sensitive to variations in the eccentricity and that the nonlinear coeffcient of the plunge spring is less influential than the nonlinear coeffcient of the torsional spring on the harvester’s performance.

  5. Optimized tapered dipole nanoantenna as efficient energy harvester.

    Science.gov (United States)

    El-Toukhy, Youssef M; Hussein, Mohamed; Hameed, Mohamed Farhat O; Heikal, A M; Abd-Elrazzak, M M; Obayya, S S A

    2016-07-11

    In this paper, a novel design of tapered dipole nanoantenna is introduced and numerically analyzed for energy harvesting applications. The proposed design consists of three steps tapered dipole nanoantenna with rectangular shape. Full systematic analysis is carried out where the antenna impedance, return loss, harvesting efficiency and field confinement are calculated using 3D finite element frequency domain method (3D-FEFD). The structure geometrical parameters are optimized using particle swarm algorithm (PSO) to improve the harvesting efficiency and reduce the return loss at wavelength of 500 nm. A harvesting efficiency of 55.3% is achieved which is higher than that of conventional dipole counterpart by 29%. This enhancement is attributed to the high field confinement in the dipole gap as a result of multiple tips created in the nanoantenna design. Furthermore, the antenna input impedance is tuned to match a wide range of fabricated diode based upon the multi-resonance characteristic of the proposed structure.

  6. Organoruthenium Complexes for Solar Energy Harvesting

    NARCIS (Netherlands)

    Wadman, S.H.

    2008-01-01

    One of the greatest challenges of this time is providing the world with the energy it needs to sustain human kind's current standard of living. Solar energy is the most abundant and ubiquitous renewable energy source available, and as such it holds great promises. Traditionally, the field of solar e

  7. Energy harvesting schemes for building interior environment monitoring

    Science.gov (United States)

    Zylka, Pawel; Pociecha, Dominik

    2016-11-01

    A vision to supply microelectronic devices without batteries making them perpetual or extending time of service in battery-oriented mobile supply schemes is the driving force of the research related to ambient energy harvesting. Energy harnessing aims thus at extracting energy from various ambient energy "pools", which generally are cost- or powerineffective to be scaled up for full-size, power-plant energy generation schemes supplying energy in electric form. These include - but are not limited to - waste heat, electromagnetic hum, vibrations, or human-generated power in addition to traditional renewable energy resources like water flow, tidal and wind energy or sun radiation which can also be exploited at the miniature scale by energy scavengers. However, in case of taking advantage of energy harvesting strategies to power up sensors monitoring environment inside buildings adaptable energy sources are restrained to only some which additionally are limited in spatial and temporal accessibility as well as available power. The paper explores experimentally an energy harvesting scheme exploiting human kinesis applicable in indoor environment for supplying a wireless indoor micro-system, monitoring ambient air properties (pressure, humidity and temperature).

  8. A new figure of merit for wideband vibration energy harvesters

    Science.gov (United States)

    Liu, W. Q.; Badel, A.; Formosa, F.; Wu, Y. P.

    2015-12-01

    The performance evaluation method is a very important part in the field of vibration energy harvesting. It provides the ability to compare and rate different vibration energy harvesters (VEHs). Considering the lack of a well-recognized tool, this article proposed a new systematic figure of merit for the appraisement of wideband VEHs. Extensive investigations are first performed for some classic figures for linear VEHs. With the common fundamental information obtained, the proposed figure integrates four essential factors: the revised energy harvester effectiveness, the mechanical quality factor, the normalized bandwidth and the effective mass density. Special considerations are devoted to the properties of wideband VEHs about the operation range and the average power in this domain which are related to the performance target of stable power output. Afterward, this new figure is applied to some literature VEHs and demonstrated to present good evaluations of wideband VEHs. Moreover, it exhibits the ability to point out the improvement information of the concerned VEHs further developments.

  9. ANALYSIS OF PIEZOELECTRIC ENERGY HARVESTING DEVICE WITH ADJUSTABLE RESONANCE FREQUENCY

    Institute of Scientific and Technical Information of China (English)

    Jiang Lei; Li Yuejuan; Marvin Cheng

    2012-01-01

    This paper presents an analytic method that adjusts resonance frequency of a piezoelectric vibration energy harvester.A mathematical model that estimates resonance frequency of cantilever is also proposed.Through moving an attached mass and changing its weight on the cantilever beam,resonance frequency of adopted piezoelectric device can be adjusted to match the frequency of ambient vibration sources,which is critical in order to harvest maximum amount of energy.The theoretical results are validated by experiments that move different masses along experimental cantilever beams.The results demonstrate that resonance frequency can be adjusted by an attached mass located at different positions on the cantilever beam.Different combinations of operational conditions that harvest maximum amount of energy are also discussed in this paper.

  10. Inverse design of nonlinearity in energy harvesters for optimum damping

    Science.gov (United States)

    Ghandchi Tehrani, Maryam; Elliott, S. J.

    2016-09-01

    This paper presents the inverse design method for the nonlinearity in an energy harvester in order to achieve an optimum damping. A single degree-of-freedom electromechanical oscillator is considered as an energy harvester, which is subjected to a harmonic base excitation. The harvester has a limited throw due to the physical constraint of the device, which means that the amplitude of the relative displacement between the mass of the harvester and the base cannot exceed a threshold when the device is driven at resonance and beyond a particular amplitude. This physical constraint requires the damping of the harvester to be adjusted for different excitation amplitudes, such that the relative displacement is controlled and maintained below the limit. For example, the damping can be increased to reduce the amplitude of the relative displacement. For high excitation amplitudes, the optimum damping is, therefore, dependent on the amplitude of the base excitation, and can be synthesised by a nonlinear function. In this paper, a nonlinear function in the form of a bilinear is considered to represent the damping model of the device. A numerical optimisation using Matlab is carried out to fit a curve to the amplitude-dependent damping in order to determine the optimum bilinear model. The nonlinear damping is then used in the time-domain simulations and the relative displacement and the average harvested power are obtained. It is demonstrated that the proposed nonlinear damping can maintain the relative displacement of the harvester at its maximum level for a wide range of excitation, therefore providing the optimum condition for power harvesting.

  11. Flexible hybrid energy cell for simultaneously harvesting thermal, mechanical, and solar energies.

    Science.gov (United States)

    Yang, Ya; Zhang, Hulin; Zhu, Guang; Lee, Sangmin; Lin, Zong-Hong; Wang, Zhong Lin

    2013-01-22

    We report the first flexible hybrid energy cell that is capable of simultaneously or individually harvesting thermal, mechanical, and solar energies to power some electronic devices. For having both the pyroelectric and piezoelectric properties, a polarized poly(vinylidene fluoride) (PVDF) film-based nanogenerator (NG) was used to harvest thermal and mechanical energies. Using aligned ZnO nanowire arrays grown on the flexible polyester (PET) substrate, a ZnO-poly(3-hexylthiophene) (P3HT) heterojunction solar cell was designed for harvesting solar energy. By integrating the NGs and the solar cells, a hybrid energy cell was fabricated to simultaneously harvest three different types of energies. With the use of a Li-ion battery as the energy storage, the harvested energy can drive four red light-emitting diodes (LEDs).

  12. Energy Harvesting Systems and Methods of Assembling Same

    Science.gov (United States)

    Cepeda-Rizo, Juan (Inventor); Ganapathi, Gani B. (Inventor)

    2013-01-01

    A method of assembling an energy harvesting system is provided. The method includes coupling at least one energy storage device in flow communication with at least one apparatus that is configured to generate thermal energy and to transfer the thermal energy into at least one fluid stream. The energy storage device is configured to store the fluid stream. Moreover, the method includes coupling at least one fluid transfer device downstream from the energy storage device. The fluid transfer device receives the fluid stream from the energy storage device. A bladeless turbine is coupled in flow communication with the fluid transfer device, wherein the bladeless turbine receives the fluid stream to generate power.

  13. Harvesting renewable energy from Earth's mid-infrared emissions.

    Science.gov (United States)

    Byrnes, Steven J; Blanchard, Romain; Capasso, Federico

    2014-03-18

    It is possible to harvest energy from Earth's thermal infrared emission into outer space. We calculate the thermodynamic limit for the amount of power available, and as a case study, we plot how this limit varies daily and seasonally in a location in Oklahoma. We discuss two possible ways to make such an emissive energy harvester (EEH): A thermal EEH (analogous to solar thermal power generation) and an optoelectronic EEH (analogous to photovoltaic power generation). For the latter, we propose using an infrared-frequency rectifying antenna, and we discuss its operating principles, efficiency limits, system design considerations, and possible technological implementations.

  14. Harvesting renewable energy from Earth's mid-infrared emissions

    KAUST Repository

    Byrnes, S. J.

    2014-03-03

    It is possible to harvest energy from Earth\\'s thermal infrared emission into outer space. We calculate the thermodynamic limit for the amount of power available, and as a case study, we plot how this limit varies daily and seasonally in a location in Oklahoma. We discuss two possible ways to make such an emissive energy harvester (EEH): A thermal EEH (analogous to solar thermal power generation) and an optoelectronic EEH (analogous to photovoltaic power generation). For the latter, we propose using an infrared-frequency rectifying antenna, and we discuss its operating principles, efficiency limits, system design considerations, and possible technological implementations.

  15. An Inductorless Self-Controlled Rectifier for Piezoelectric Energy Harvesting

    Directory of Open Access Journals (Sweden)

    Shaohua Lu

    2015-11-01

    Full Text Available This paper presents a high-efficiency inductorless self-controlled rectifier for piezoelectric energy harvesting. High efficiency is achieved by discharging the piezoelectric device (PD capacitance each time the current produced by the PD changes polarity. This is achieved automatically without the use of delay lines, thereby making the proposed circuit compatible with any type of PD. In addition, the proposed rectifier alleviates the need for an inductor, making it suitable for on-chip integration. Reported experimental results show that the proposed rectifier can harvest up to 3.9 times more energy than a full wave bridge rectifier.

  16. Contacting mode operation of work function energy harvester

    Science.gov (United States)

    Varpula, A.; Laakso, S. J.; Havia, T.; Kyynäräinen, J.; Prunnila, M.

    2014-11-01

    The work function energy harvester (WFEH) is a variable capacitance vibration energy harvester where the charging of the capacitor electrodes is driven by the work function difference of the electrode materials. In this work, we investigate operation modes of the WFEH by utilizing a macroscopic parallel plate capacitor with Cu and Al electrodes and varying plate distance. We show that by charging the electrodes of the WFEH by letting the electrode plates touch during the operation a significant output power enhancement can be achieved in comparison to the case where the electrodes are charged and discharged only through a load resistor.

  17. Applications of energy harvesting for ultralow power technology

    Science.gov (United States)

    Pop-Vadean, A.; Pop, P. P.; Barz, C.; Chiver, O.

    2015-06-01

    Ultra-low-power (ULP) technology is enabling a wide range of new applications that harvest ambient energy in very small amounts and need little or no maintenance - self-sustaining devices that are capable of perpetual or nearly perpetual operation. These new systems, which are now appearing in industrial and consumer electronics, also promise great changes in medicine and health. Until recently, the idea of micro-scale energy harvesting, and collecting miniscule amounts of ambient energy to power electronic systems, was still limited to research proposals and laboratory experiments.Today an increasing number of systems are appearing that take advantage of light, vibrations and other forms of previously wasted environmental energy for applications where providing line power or maintaining batteries is inconvenient. In the industrial world, where sensors gather information from remote equipment and hazardous processes; in consumer electronics, where mobility and convenience are served; and in medical systems, with unique requirements for prosthetics and non-invasive monitoring, energy harvesting is rapidly expanding into new applications.This paper serves as a survey for applications of energy harvesting for ultra low power technology based on various technical papers available in the public domain.

  18. Optimal energy harvesting from vortex-induced vibrations of cables.

    Science.gov (United States)

    Antoine, G O; de Langre, E; Michelin, S

    2016-11-01

    Vortex-induced vibrations (VIV) of flexible cables are an example of flow-induced vibrations that can act as energy harvesting systems by converting energy associated with the spontaneous cable motion into electricity. This work investigates the optimal positioning of the harvesting devices along the cable, using numerical simulations with a wake oscillator model to describe the unsteady flow forcing. Using classical gradient-based optimization, the optimal harvesting strategy is determined for the generic configuration of a flexible cable fixed at both ends, including the effect of flow forces and gravity on the cable's geometry. The optimal strategy is found to consist systematically in a concentration of the harvesting devices at one of the cable's ends, relying on deformation waves along the cable to carry the energy towards this harvesting site. Furthermore, we show that the performance of systems based on VIV of flexible cables is significantly more robust to flow velocity variations, in comparison with a rigid cylinder device. This results from two passive control mechanisms inherent to the cable geometry: (i) the adaptability to the flow velocity of the fundamental frequencies of cables through the flow-induced tension and (ii) the selection of successive vibration modes by the flow velocity for cables with gravity-induced tension.

  19. Optimal energy harvesting from vortex-induced vibrations of cables

    Science.gov (United States)

    Antoine, G. O.; de Langre, E.; Michelin, S.

    2016-11-01

    Vortex-induced vibrations (VIV) of flexible cables are an example of flow-induced vibrations that can act as energy harvesting systems by converting energy associated with the spontaneous cable motion into electricity. This work investigates the optimal positioning of the harvesting devices along the cable, using numerical simulations with a wake oscillator model to describe the unsteady flow forcing. Using classical gradient-based optimization, the optimal harvesting strategy is determined for the generic configuration of a flexible cable fixed at both ends, including the effect of flow forces and gravity on the cable's geometry. The optimal strategy is found to consist systematically in a concentration of the harvesting devices at one of the cable's ends, relying on deformation waves along the cable to carry the energy towards this harvesting site. Furthermore, we show that the performance of systems based on VIV of flexible cables is significantly more robust to flow velocity variations, in comparison with a rigid cylinder device. This results from two passive control mechanisms inherent to the cable geometry: (i) the adaptability to the flow velocity of the fundamental frequencies of cables through the flow-induced tension and (ii) the selection of successive vibration modes by the flow velocity for cables with gravity-induced tension.

  20. Which is better, electrostatic or piezoelectric energy harvesting systems?

    Science.gov (United States)

    Elliott, A. D. T.; Miller, L. M.; Halvorsen, E.; Wright, P. K.; Mitcheson, P. D.

    2015-12-01

    This paper answers the often asked, and until now inadequately answered, question of which MEMS compatible transducer type achieves the best power density in an energy harvesting system. This question is usually poorly answered because of the number of variables which must be taken into account and the multi-domain nature of the modelling and optimisation. The work here includes models of the mechanics, transducer and the power processing circuits (e.g. rectification and battery management) which in turn include detailed semiconductor models. It is shown that electrostatic harvesters perform better than piezoelectric harvesters at low accelerations, due to lower energy losses, and the reverse is generally true at high accelerations. At very high accelerations using MEMS-scale devices the dielectric breakdown limit in piezoelectric energy harvesters severely decreases their performance thus electrostatics are again preferred. Using the insights gained in this comparison, the optimal transduction mechanism can be chosen as a function of harvesting operating frequency, acceleration and device size.

  1. Finite element modeling of electrically rectified piezoelectric energy harvesters

    Science.gov (United States)

    Wu, P. H.; Shu, Y. C.

    2015-09-01

    Finite element models are developed for designing electrically rectified piezoelectric energy harvesters. They account for the consideration of common interface circuits such as the standard and parallel-/series-SSHI (synchronized switch harvesting on inductor) circuits, as well as complicated structural configurations such as arrays of piezoelectric oscillators. The idea is to replace the energy harvesting circuit by the proposed equivalent load impedance together with the capacitance of negative value. As a result, the proposed framework is capable of being implemented into conventional finite element solvers for direct system-level design without resorting to circuit simulators. The validation based on COMSOL simulations carried out for various interface circuits by the comparison with the standard modal analysis model. The framework is then applied to the investigation on how harvested power is reduced due to fabrication deviations in geometric and material properties of oscillators in an array system. Remarkably, it is found that for a standard array system with strong electromechanical coupling, the drop in peak power turns out to be insignificant if the optimal load is carefully chosen. The second application is to design broadband energy harvesting by developing array systems with suitable interface circuits. The result shows that significant broadband is observed for the parallel (series) connection of oscillators endowed with the parallel-SSHI (series-SSHI) circuit technique.

  2. Tailored piezoelectric thin films for energy harvester

    NARCIS (Netherlands)

    Wan, X.

    2013-01-01

    Piezoelectric materials are excellent materials to transfer mechanical energy into electrical energy, which can be stored and used to power other devices. PiezoMEMS is a good way to combine silicon wafer processing and piezoelectric thin film technology and lead to a variety of miniaturized and prem

  3. Harvesting alternate energies from our planet

    Science.gov (United States)

    Rath, Bhakta B.

    2009-04-01

    Recent price fluctuations have focused attention on the phenomenal increase of global energy consumption in recent years. We have almost reached a peak in global oil production. Total world consumption of oil will rise by nearly 60% between 1999 and 2020. In 1999 consumption was 86 million barrels of oil per day, which has reached a peak of production extracted from most known oil reserves. These projections, if accurate, will present an unprecedented crisis to the global economy and industry. As an example, in the United States, nearly 40% of energy usage is provided by petroleum, of which nearly a third is used in transportation. An aggressive search for alternate energy sources, both renewable and nonrenewable, is vital. This article will review national and international perspectives on the exploration of alternate energies with a focus on energy derivable from the ocean.

  4. Feasibility of energy harvesting techniques for wearable medical devices.

    Science.gov (United States)

    Voss, Thaddaeus J; Subbian, Vignesh; Beyette, Fred R

    2014-01-01

    Wearable devices are arguably one of the most rapidly growing technologies in the computing and health care industry. These systems provide improved means of monitoring health status of humans in real-time. In order to cope with continuous sensing and transmission of biological and health status data, it is desirable to move towards energy autonomous systems that can charge batteries using passive, ambient energy. This not only ensures uninterrupted data capturing, but could also eliminate the need to frequently remove, replace, and recharge batteries. To this end, energy harvesting is a promising area that can lead to extremely power-efficient portable medical devices. This paper presents an experimental prototype to study the feasibility of harvesting two energy sources, solar and thermoelectric energy, in the context of wearable devices. Preliminary results show that such devices can be powered by transducing ambient energy that constantly surrounds us.

  5. Radio Frequency Energy Harvesting for Long Lifetime Wireless Sensor Networks

    DEFF Research Database (Denmark)

    Han, Bo; Nielsen, Rasmus Hjorth; Prasad, Ramjee

    2014-01-01

    In wireless sensor networks energy scarcity is a major concern on energy consumption, and by properly designing on the node network architecture or selecting efficient protocols of the networks, the maximum energy can be reduced significantly thereby increasing the network lifetime. However......, in most of the cases, the sensor nodes are either powered by non-replaceable batteries, or there will be a considerable replacement cost. Thus a self-rechargeable sensor node design is necessary: the sensor node should be able to harvest energy from the environment. Among the existing techniques...... loss of the RF signals. On the node level, a virtual floating gate based CMOS biasing is used for the energy conversion circuit. With the proposed technique, the sensor node is able to harvest the energy from base station up to 30 meters....

  6. Analyzing and Modelling Energy Harvesting Wireless Sensor Networks

    OpenAIRE

    Ventura Jaume, Joan

    2011-01-01

    Projecte final de carrera fet en col.laboració amb Northeastern University. English: Energy harvesting is envisaged as an enabling technology to meet the growing energy demands of the 21st century. The current state of the art allows tapping into several physical and naturally existing sources, such as solar, wind, vibration, RF scavenging, among others. However, there is a lack of theoretical models that can predict future consumption and residual availability of energy in a sensor node e...

  7. 3-D Enzymatic Nanomaterial Architectures for Energy Harvesting

    Science.gov (United States)

    2016-06-30

    Logan et al., 2006; Luckarift et al., 2014). Since the chemical energy stored in ubiquitous fuels available in the environment is transformed into...such as enzymatic fuel cells, photo- bio energy harvesting devices, nano-biosensors, bio-actuators and other bio-nano-interfacial architectures is the...fossil fuels dwindling, there is an urgent need to find cheap, renewable, and alternate forms of energy using naturally abundant resources such as

  8. Degradation of bimorph piezoelectric bending beams in energy harvesting applications

    Science.gov (United States)

    Pillatsch, P.; Xiao, B. L.; Shashoua, N.; Gramling, H. M.; Yeatman, E. M.; Wright, P. K.

    2017-03-01

    Piezoelectric energy harvesting is an attractive alternative to battery powering for wireless sensor networks. However, in order for it to be a viable long term solution the fatigue life needs to be assessed. Many vibration harvesting devices employ bimorph piezoelectric bending beams as transduction elements to convert mechanical to electrical energy. This paper introduces two degradation studies performed under symmetrical and asymmetrical sinusoidal loading. It is shown that besides a loss in output power, the most dramatic effect of degradation is a shift in resonance frequency which is highly detrimental to resonant harvester designs. In addition, micro-cracking was shown to occur predominantly in piezoelectric layers under tensile stress. This opens the opportunity for increased life time through compressive operation or pre-loading of piezoceramic layers.

  9. Dynamics of energy harvesting backpack with human being interaction

    Science.gov (United States)

    Yuan, Yue; Zuo, Lei

    2016-04-01

    In last ten years, a lot of researchers have begun to look into obtaining electricity from the movement between human and their backpack that occurs during walking. In this paper, an innovative, elastically-suspended backpack with mechanical motion rectifier (MMR) based energy harvester is developed to generate electricity with high efficiency and reliability. Up to 28 Watts peak electrical power can be produced by the MMR based backpack energy harvester. A dynamic model for the system is presented along with experimental results. Three dual mass models for different distinct harvesters: pure viscous, non MMR, and MMR, are proposed, and a comparison in the output power and human comfort between the three models is discussed.

  10. Innovative thermal energy harvesting for future autonomous applications

    Science.gov (United States)

    Monfray, Stephane

    2013-12-01

    As communicating autonomous systems market is booming, the role of energy harvesting will be a key enabler. As example, heat is one of the most abundant energy sources that can be converted into electricity in order to power circuits. Harvesting systems that use wasted heat open new ways to power autonomous sensors when the energy consumption is low, or to create systems of power generators when the conversion efficiency is high. The combination of different technologies (low power μ-processors, μ-batteries, radio, sensors...) with new energy harvesters compatible with large varieties of use-cases with allow to address this booming market. Thanks to the conjunction of ultra-low power electronic development, 3D technologies & Systems in Package approaches, the integration of autonomous sensors and electronics with ambient energy harvesting will be achievable. The applications are very wide, from environment and industrial sensors to medical portable applications, and the Internet of things may also represent in the future a several billions units market.

  11. Radio-frequency energy harvesting for wearable sensors.

    Science.gov (United States)

    Borges, Luís M; Chávez-Santiago, Raul; Barroca, Norberto; Velez, Fernando José; Balasingham, Ilangko

    2015-02-01

    The use of wearable biomedical sensors for the continuous monitoring of physiological signals will facilitate the involvement of the patients in the prevention and management of chronic diseases. The fabrication of small biomedical sensors transmitting physiological data wirelessly is possible as a result of the tremendous advances in ultra-low power electronics and radio communications. However, the widespread adoption of these devices depends very much on their ability to operate for long periods of time without the need to frequently change, recharge or even use batteries. In this context, energy harvesting (EH) is the disruptive technology that can pave the road towards the massive utilisation of wireless wearable sensors for patient self-monitoring and daily healthcare. Radio-frequency (RF) transmissions from commercial telecommunication networks represent reliable ambient energy that can be harvested as they are ubiquitous in urban and suburban areas. The state-of-the-art in RF EH for wearable biomedical sensors specifically targeting the global system of mobile 900/1800 cellular and 700 MHz digital terrestrial television networks as ambient RF energy sources are showcased. Furthermore, guidelines for the choice of the number of stages for the RF energy harvester are presented, depending on the requirements from the embedded system to power supply, which is useful for other researchers that work in the same area. The present authors' recent advances towards the development of an efficient RF energy harvester and storing system are presented and thoroughly discussed too.

  12. Micro energy harvesting from ambient motion : modeling, simulation and design

    Energy Technology Data Exchange (ETDEWEB)

    Blystad, Lars-Cyril

    2012-07-01

    Vibration energy harvesting is the process of converting available ambient kinetic energy into useful electrical energy. It can be done on large scale with e.g. a wind-driven turbine. This thesis deals with small scale energy harvesters that are suitable for fabrication in Micro electromechanical Systems (MEMS) technologies. Such MEMS energy harvesters have the potential to supply power for micro power devices. Modeling, simulation and design of MEMS vibration energy harvesters are the foci of this thesis. Transduction mechanisms that are covered are electrostatic and piezoelectric. Electric equivalent circuits are obtained for the use in electromechanical simulations with the circuit simulator SPICE. The feasibility of simulating both narrow- and broadband vibrations, to model different external driving forces, in a standard circuit simulator is demonstrated. Comparisons of the har- vesters performance for different excitations are presented. A selection of passive and active power conditioning circuits is investigated and their performances compared. The active nonlinear switching conversion circuitry performs better than simple passive circuitry, especially when mechanical end stops are in effect. The active switching circuits give higher electromechanical damping, and thus can be driven at higher acceleration amplitudes before end stops are engaged. Mechanical end stops have to be present in all MEMS vibrational energy harvesters. Either due to space limitations, reliability issues, Simliberate introduction of nonlinearities or a combination of these. ulations in the thesis include mechanical end stops and thus include the corresponding nonlinearities introduced in the system. When the mechanical end stops are hit by the proof mass during high-amplitude vibrations, nonlinear effects such as saturation and jumps are present. The end stops increase the effective bandwidth at large acceleration amplitudes. End stops limit the output power for sinusoidal

  13. An Energy Aware Adaptive Sampling Algorithm for Energy Harvesting WSN with Energy Hungry Sensors

    Directory of Open Access Journals (Sweden)

    Bruno Srbinovski

    2016-03-01

    Full Text Available Wireless sensor nodes have a limited power budget, though they are often expected to be functional in the field once deployed for extended periods of time. Therefore, minimization of energy consumption and energy harvesting technology in Wireless Sensor Networks (WSN are key tools for maximizing network lifetime, and achieving self-sustainability. This paper proposes an energy aware Adaptive Sampling Algorithm (ASA for WSN with power hungry sensors and harvesting capabilities, an energy management technique that can be implemented on any WSN platform with enough processing power to execute the proposed algorithm. An existing state-of-the-art ASA developed for wireless sensor networks with power hungry sensors is optimized and enhanced to adapt the sampling frequency according to the available energy of the node. The proposed algorithm is evaluated using two in-field testbeds that are supplied by two different energy harvesting sources (solar and wind. Simulation and comparison between the state-of-the-art ASA and the proposed energy aware ASA (EASA in terms of energy durability are carried out using in-field measured harvested energy (using both wind and solar sources and power hungry sensors (ultrasonic wind sensor and gas sensors. The simulation results demonstrate that using ASA in combination with an energy aware function on the nodes can drastically increase the lifetime of a WSN node and enable self-sustainability. In fact, the proposed EASA in conjunction with energy harvesting capability can lead towards perpetual WSN operation and significantly outperform the state-of-the-art ASA.

  14. Piezoelectric energy harvesting from transverse galloping of bluff bodies

    Science.gov (United States)

    Abdelkefi, A.; Hajj, M. R.; Nayfeh, A. H.

    2013-01-01

    The concept of harvesting energy from transverse galloping oscillations of a bluff body with different cross-section geometries is investigated. The energy is harvested by attaching a piezoelectric transducer to the transverse degree of freedom of the body. The power levels that can be generated from these vibrations and the variations of these levels with the load resistance, cross-section geometry, and freestream velocity are determined. A representative model that accounts for the transverse displacement of the bluff body and harvested voltage is presented. The quasi-steady approximation is used to model the aerodynamic loads. A linear analysis is performed to determine the effects of the electrical load resistance and the cross-section geometry on the onset of galloping, which is due to a Hopf bifurcation. The normal form of this bifurcation is derived to determine the type (supercritical or subcritical) of the instability and to characterize the effects of the linear and nonlinear parameters on the level of harvested power near the bifurcation. The results show that the electrical load resistance and the cross-section geometry affect the onset speed of galloping. The results also show that the maximum levels of harvested power are accompanied with minimum transverse displacement amplitudes for all considered (square, D, and triangular) cross-section geometries, which points to the need for performing a coupled analysis of the system.

  15. Validation of energy harvest modeling for X14 system

    Science.gov (United States)

    Finot, Marc; MacDonald, Bob; Lance, Tamir

    2012-10-01

    Skyline Solar has developed a second generation medium concentration photovoltaic system with an optical concentration of around 14. The energy harvest model based on the first generation system has been updated and improved using field data. The model combines a bottom-up modeling approach based on performance of subcomponents such as mirrors and cells with a top-down approach based on measuring the system output under different environmental conditions. Improvement of the model includes the effect of non-uniformity of the light on the panel. The predicted energy ratio (ratio between the observed energy and expected energy) has been measured over a 10-month period and shows monthly variability below 2%, resulting in high confidence level for the mean of the expected energy harvest.

  16. Small scale wind energy harvesting with maximum power tracking

    Directory of Open Access Journals (Sweden)

    Joaquim Azevedo

    2015-07-01

    Full Text Available It is well-known that energy harvesting from wind can be used to power remote monitoring systems. There are several studies that use wind energy in small-scale systems, mainly with wind turbine vertical axis. However, there are very few studies with actual implementations of small wind turbines. This paper compares the performance of horizontal and vertical axis wind turbines for energy harvesting on wireless sensor network applications. The problem with the use of wind energy is that most of the time the wind speed is very low, especially at urban areas. Therefore, this work includes a study on the wind speed distribution in an urban environment and proposes a controller to maximize the energy transfer to the storage systems. The generated power is evaluated by simulation and experimentally for different load and wind conditions. The results demonstrate the increase in efficiency of wind generators that use maximum power transfer tracking, even at low wind speeds.

  17. Energy adaptive MAC protocol for IEEE 802.15.7 with energy harvesting

    Science.gov (United States)

    Wang, Hong-qiao; Chi, Xue-fen; Zhao, Lin-lin

    2016-09-01

    The medium access control (MAC) protocol for indoor visible light communication (VLC) with energy harvesting is explored in this paper. The unfairness of throughput exists among devices due to the significant difference of their energy harvesting rates which changes with distance, acceptance angle and the obstruction probability. We propose an energy harvesting model, a new obstruction probability model and an energy adaptive contention algorithm to overcome the unfairness problem. This device can adjust its contention window according to the energy harvesting rate. As a result, the device with lower energy harvesting rate can get shorter contention window to improve its transmission opportunity. Simulation results show that our MAC protocol can achieve a higher degree of fairness.

  18. Single/Dual-Polarized Infrared Rectenna for Solar Energy Harvesting

    Directory of Open Access Journals (Sweden)

    S. H. Zainud-Deen

    2016-05-01

    Full Text Available Single and dual linearly-polarized receiving mode nanoantennas are designed for solar energy harvesting at 28.3 THz. The infrared rectennas are used to harvest the solar energy and converting it to electrical energy.  The proposed infrared rectenna is a thin dipole made of gold and printed on a silicon dioxide substrate. Different shapes of the dipole arms have been investigated for maximum collected energy. The two poles of the dipole have been determined in a rectangular, circular and rhombus shapes. The rectenna dipole is used to concentrate the electromagnetic energy into a small localized area at the inner tips of the gap between the dipole arms. The dimensions of the different dipole shapes are optimized for maximum near electric field intensity at a frequency of 28.3 THz. A Metal Insulator Metal (MIM diode is incorporated with the nanoantenna dipole to rectify the received energy. The receiving efficiency of the solar energy collector with integrated MIM diode has been investigated. A dual-polarized, four arms, rhombus shaped nanoantenna dipole for solar energy harvesting has been designed and optimized for 28.3 THz applications.

  19. Energy harvesting from controlled buckling of piezoelectric beams

    Science.gov (United States)

    Ansari, M. H.; Karami, M. Amin

    2015-11-01

    A piezoelectric vibration energy harvester is presented that can generate electricity from the weight of passing cars or crowds. The energy harvester consists of a piezoelectric beam, which buckles when the device is stepped on. The energy harvester can have a horizontal or vertical configuration. In the vertical (direct) configuration, the piezoelectric beam is vertical and directly sustains the weight of the vehicles or people. In the horizontal (indirect) configuration, the vertical weight is transferred to a horizontal axial force through a scissor-like mechanism. Buckling of the beam results in significant stresses and, thus, large power production. However, if the beam’s buckling is not controlled, the beam will fracture. To prevent this, the axial deformation is constrained to limit the deformations of the beam. In this paper, the energy harvester is analytically modeled. The considered piezoelectric beam is a general non-uniform beam. The natural frequencies, mode shapes, and the critical buckling force corresponding to each mode shape are calculated. The electro-mechanical coupling and the geometric nonlinearities are included in the model. The design criteria for the device are discussed. It is demonstrated that a device, realized with commonly used piezoelectric patches, can generate tens of milliwatts of power from passing car traffic. The proposed device could also be implemented in the sidewalks or integrated in shoe soles for energy generation. One of the key features of the device is its frequency up-conversion characteristics. The piezoelectric beam undergoes free vibrations each time the weight is applied to or removed from the energy harvester. The frequency of the free vibrations is orders of magnitude larger than the frequency of the load. The device is, thus, both efficient and insensitive to the frequency of the force excitations.

  20. Low Frequency Vibration Energy Harvesting using Diamagnetically Stabilized Magnet Levitation

    Science.gov (United States)

    Palagummi, Sri Vikram

    Over the last decade, vibration-based energy harvesting has provided a technology push on the feasibility of self-powered portable small electronic devices and wireless sensor nodes. Vibration energy harvesters in general transduce energy by damping out the environmentally induced relative emotion through either a cantilever beam or an equivalent suspension mechanism with one of the transduction mechanisms, like, piezoelectric, electrostatic, electromagnetic or magnetostrictive. Two major challenges face the present harvesters in literature, one, they suffer from the unavoidable mechanical damping due to internal friction present in the systems, second, they cannot operate efficiently in the low frequency range (magnet levitation mechanisms which can work efficiently as a vibration energy harvester in the low frequency range are discussed in this work. First, a mono-stable vertical diamagnetic levitation (VDL) based vibration energy harvester (VEH) is discussed. The harvester consists of a lifting magnet (LM), a floating magnet (FM) and two diamagnetic plates (DPs). The LM balances out the weight of the FM and stability is brought about by the repulsive effect of the DPs, made of pyrolytic graphite. Two thick cylindrical coils, placed in grooves which are engraved in the DPs, are used to convert the mechanical energy into electrical energy. Experimental frequency response of the system is validated by the theoretical analysis which showed that the VEH works in a low frequency range but sufficient levitation gap was not achieved and the frequency response characteristic of the system was effectively linear. To overcome these challenges, the influence of the geometry of the FM, the LM, and the DP were parametrically studied to assess their effects on the levitation gap, size of the system and the natural frequency. For efficient vibration energy harvesting using the VDL system, ways to mitigate eddy current damping and a coil geometry for transduction were critically

  1. Metamaterials-based enhanced energy harvesting: A review

    Science.gov (United States)

    Chen, Zhongsheng; Guo, Bin; Yang, Yongmin; Cheng, Congcong

    2014-04-01

    Advances in low power design open the possibility to harvest ambient energies to power directly the electronics or recharge a secondary battery. The key parameter of an energy harvesting (EH) device is its efficiency, which strongly depends on the conversion medium. To address this issue, metamaterials, artificial materials and structures with exotic properties, have been introduced for EH in recent years. They possess unique properties not easily achieved using naturally occurring materials, such as negative stiffness, mass, Poisson's ratio, and refractive index. The goal of this paper is to review the fundamentals, recent progresses and future directions in the field of metamaterials-based enhanced energy harvesting. An introduction on EH followed by the classification of potential metamaterials for EH is presented. A number of theoretical and experimental studies on metamaterials-based EH are outlined, including phononic crystals, acoustic metamaterials, and electromagnetic metamaterials. Finally, we give an outlook on future directions of metamaterials-based energy harvesting research including but not limited to active metamaterials-based EH, metamaterials-based thermal EH, and metamaterials-based multifunctional EH capabilities.

  2. An Energy Harvesting Underwater Acoustic Transmitter for Aquatic Animals

    Energy Technology Data Exchange (ETDEWEB)

    Li, Huidong; Tian, Chuan; Lu, Jun; Myjak, Mitchell J.; Martinez, Jayson J.; Brown, Richard S.; Deng, Zhiqun Daniel

    2016-09-20

    This paper presents a self-powered underwater acoustic transmitter using a piezoelectric beam to harvest the mechanical energy from fish swimming. This transmitter does not require a battery and is demonstrated in live fish. It transmits an acoustic waveform as the implanted fish swims. It enables long-term monitoring of aquatic animals.

  3. MEMS fabricated energy harvesting device with 2D resonant structure

    DEFF Research Database (Denmark)

    Crovetto, Andrea; Wang, Fei; Triches, Marco

    This paper reports on a MEMS energy harvester able to generate power from two perpendicular ambient vibration directions. CYTOP polymer is used both as the electret material for electrostatic transduction and as a bonding interface for low-temperature wafer bonding. With final chip size of ~1 cm2...

  4. Nanoscale domain patterns and a concept for an energy harvester

    Science.gov (United States)

    Renuka Balakrishna, Ananya; Huber, John E.

    2016-10-01

    The current work employs a phase-field model to test the stability of nanoscale periodic domain patterns, and to explore the application of one pattern in an energy harvester device. At first, the stability of several periodic domain patterns with in-plane polarizations is tested under stress-free and electric field-free conditions. It is found that simple domain patterns with stripe-like features are stable, while patterns with more complex domain configurations are typically unstable at the nanoscale. Upon identifying a stable domain pattern with suitable properties, a conceptual design of a thin film energy harvester device is explored. The harvester is modeled as a thin ferroelectric film bound to a substrate. In the initial state a periodic stripe domain pattern with zero net charge on the top electrode is modeled. On bending the substrate, a mechanical strain is induced in the film, causing polarized domains to undergo ferroelectric switching and thus generate electrical energy. The results demonstrate the working cycle of a conceptual energy harvester which, on operating at kHz frequencies, such as from vibrations in the environment, could produce an area power density of about 40 W m-2.

  5. Piezoelectric and Semiconducting Ribbon for Flexible Energy Harvesting

    Science.gov (United States)

    2012-06-08

    360k total) • Lockheed Martin, “Investigation of Wireless Energy Harvesting,” $50k total • Essig- Enright and Insley Blair Pyne Funds, “Studying... ROBERT F. SERVICE www .. sciencem ag~ or g SOE C.E VOL 328 1 6 APR~ L 201 0 Power surfing on waves Wavy strips of piezoelectric materials on

  6. Myocardial Cell Pattern on Piezoelectric Nanofiber Mats for Energy Harvesting

    Science.gov (United States)

    Liu, X.; Wang, X.; Zhao, H.; Du, Y.

    2014-11-01

    The paper presents in vitro contractile myocardial cell pattern on piezoelectric nanofiber mats with applications in energy harvesting. The cell-based energy harvester consists of myocardial cell sheet and a PDMS substrate with a PVDF nanofiber mat on. Experimentally, cultured on specifically distributed nanofiber mats, neonatal rat ventricular cardiomyocytes are characterized with the related morphology and contraction. Previously, we have come up with the concept of energy harvesting from heart beating using piezoelectric material. A bio-hybrid energy harvester combined living cardiomyocytes, PDMS polymer substrate and piezoelectric PVDF film with the electrical output of peak current 87.5nA and peak voltage 92.3mV. However, the thickness of the cardiomyocyte cultured on a two-dimensional substrate is much less than that of the piezoelectric film. The Micro Contact Printing (μCP) method used in cell pattern on the PDMS thin film has tough requirement for the film surface. As such, in this paper we fabricated nanofiber-constructed PDMS thin film to realize cell pattern due to PVDF nanofibers with better piezoelectricity and microstructures of nanofiber mats guiding cell distribution. Living cardiomyocytes patterned on those distributed piezoelectric nanofibers with the result of the same distribution as the nanofiber pattern.

  7. Development of Vibration-Based Piezoelectric Raindrop Energy Harvesting System

    Science.gov (United States)

    Wong, Chin Hong; Dahari, Zuraini

    2017-01-01

    The trend of finding new means to harvest energy has triggered numerous researches to explore the potential of raindrop energy harvesting. This paper presents an investigation on raindrop energy harvesting which compares the performance of polyvinylidene fluoride (PVDF) cantilever and bridge structure transducers and the development of a raindrop energy harvesting system. The parameters which contribute to the output voltage such as droplet size, droplets released at specific heights and dimensions of PVDF transducers are analyzed. Based on the experimental results, the outcomes have shown that the bridge structure transducer generated a higher voltage than the cantilever. Several dimensions have been tested and it was found that the 30 mm × 4 mm × 25 μm bridge structure transducer generated a relatively high AC open-circuit voltage, which is 4.22 V. The power generated by the bridge transducer is 18 μW across a load of 330 kΩ. The transducer is able to drive up a standard alternative current (AC) to direct current (DC) converter (full-wave bridge rectifier). It generated a DC voltage, V DC of 8.7 mV and 229 pW across a 330 kΩ resistor per drop. It is also capable to generate 9.3 nJ in 20 s from an actual rain event.

  8. A batch process micromachined thermoelectric energy harvester: Fabrication and characterization

    NARCIS (Netherlands)

    Su, J.; Leonov, V.; Goedbloed, M.; Andel, Y. van; Nooijer, M.C.de; Elfrink, R.; Wang, Z.; Vullers, R.J.M.

    2010-01-01

    Micromachined thermopiles are considered as a cost-effective solution for energy harvesters working at a small temperature difference and weak heat flows typical for, e.g., the human body. They can be used for powering autonomous wireless sensor nodes in a body area network. In this paper, a microma

  9. Advanced Energy Harvesting Control Schemes for Marine Renewable Energy Devices

    Energy Technology Data Exchange (ETDEWEB)

    McEntee, Jarlath [Ocean Renewable Power Company, Portland, ME (United States); Polagye, Brian [Ocean Renewable Power Company, Portland, ME (United States); Fabien, Brian [Ocean Renewable Power Company, Portland, ME (United States); Thomson, Jim [Ocean Renewable Power Company, Portland, ME (United States); Kilcher, Levi [Ocean Renewable Power Company, Portland, ME (United States); Marnagh, Cian [Ocean Renewable Power Company, Portland, ME (United States); Donegan, James [Ocean Renewable Power Company, Portland, ME (United States)

    2016-03-31

    The Advanced Energy Harvesting Control Schemes for Marine Renewable Energy Devices (Project) investigated, analyzed and modeled advanced turbine control schemes with the objective of increasing the energy harvested by hydrokinetic turbines in turbulent flow. Ocean Renewable Power Company (ORPC) implemented and validated a feedforward controller to increase power capture; and applied and tested the controls on ORPC’s RivGen® Power Systems in Igiugig, Alaska. Assessments of performance improvements were made for the RivGen® in the Igiugig environment and for ORPC’s TidGen® Power System in a reference tidal environment. Annualized Energy Production (AEP) and Levelized Cost of Energy (LCOE) improvements associated with implementation of the recommended control methodology were made for the TidGen® Power System in the DOE reference tidal environment. System Performance Advancement (SPA) goals were selected for the project. SPA targets were to improve Power to Weight Ratio (PWR) and system Availability, with the intention of reducing Levelized Cost of Electricity (LCOE). This project focused primarily reducing in PWR. Reductions in PWR of 25.5% were achieved. Reductions of 20.3% in LCOE were achieved. This project evaluated four types of controllers which were tested in simulation, emulation, a laboratory flume, and the field. The adaptive Kω2 controller performs similarly to the non-adaptive version of the same controller and may be useful in tidal channels where the mean velocity is continually evolving. Trends in simulation were largely verified through experiments, which also provided the opportunity to test assumptions about turbine responsiveness and control resilience to varying scales of turbulence. Laboratory experiments provided an essential stepping stone between simulation and implementation on a field-scale turbine. Experiments also demonstrated that using “energy loss” as a metric to differentiate between well-designed controllers operating at

  10. Energy harvesting with a slotted-cymbal transducer

    Institute of Scientific and Technical Information of China (English)

    Jiang-bo YUAN; Xiao-biao SHAN; Tao XIE; Wei-shan CHEN

    2009-01-01

    A cymbal transducer is made up of a piezoceramic disk sandwiched between two dome-shaped metal endcaps. High circumferential stresses caused by flexural motion of the metal endcaps can induce the loss of mechanical input energy. Finite element analysis shows that the radial slots fabricated in metal endcaps can release the circumferential stresses, and reduce the loss of mechanical input energy that could be converted into electrical energy. In this letter, the performance of a slotted-cymbal transducer in energy harvesting was tested. The results show that the output voltage and power of the cymbal are improved. A maximum output power of around 16 mW could be harvested from a cymbal with 18 cone radial slots across a 500kΩ resistive load, which is approximately 0.6 times more than that of the original cymbal transducer.

  11. Near-field thermodynamics: Useful work, efficiency, and energy harvesting

    Energy Technology Data Exchange (ETDEWEB)

    Latella, Ivan, E-mail: ilatella@ffn.ub.edu; Pérez-Madrid, Agustín, E-mail: agustiperezmadrid@ub.edu [Departament de Física Fonamental, Facultat de Física, Universitat de Barcelona, Martí i Franquès 1, 08028 Barcelona (Spain); Lapas, Luciano C., E-mail: luciano.lapas@pq.cnpq.br [Universidade Federal da Integração Latino-Americana, Caixa Postal 2067, 85867-970 Foz do Iguaçu (Brazil); Miguel Rubi, J., E-mail: mrubi@ub.edu [Departament de Física Fonamental, Facultat de Física, Universitat de Barcelona, Martí i Franquès 1, 08028 Barcelona (Spain); Department of Chemistry, Imperial College London, SW7 2AZ London (United Kingdom)

    2014-03-28

    We show that the maximum work that can be obtained from the thermal radiation emitted between two planar sources in the near-field regime is much larger than that corresponding to the blackbody limit. This quantity, as well as an upper bound, for the efficiency of the process is computed from the formulation of thermodynamics in the near-field regime. The case when the difference of temperatures of the hot source and the environment is small, relevant for energy harvesting, is studied in detail. We also show that thermal radiation energy conversion can be more efficient in the near-field regime. These results open new possibilities for the design of energy converters that can be used to harvest energy from sources of moderate temperature at the nanoscale.

  12. Harvesting electrostatic energy using super-hydrophobic surfaces

    Science.gov (United States)

    Pociecha, Dominik; Zylka, Pawel

    2016-11-01

    Almost all environments are now being extensively populated by miniaturized, nano-powered electronic sensor devices communicated together through wireless sensor networks building Internet of Things (IoT). Various energy harvesting techniques are being more and more frequently proposed for battery-less powering of such remote, unattended, implantable or wearable sensors or other low-power electronic gadgets. Energy harvesting relays on extracting energy from the ambient sources readily accessible at the sensor location and converting it into electrical power. The paper exploits possibility of generating electric energy safely accessible for nano-power electronics using tribo-electric and electrostatic induction phenomena displayed at super-hydrophobic surfaces impinged by water droplets. Mechanism of such interaction is discussed and illustrated by experimental results.

  13. Medium Access Control in Energy Harvesting - Wireless Sensor Networks

    DEFF Research Database (Denmark)

    Fafoutis, Xenofon

    Control (MAC) protocols that are following the receiver-initiated paradigm of asynchronous communication. According to the receiver-initiated paradigm the communication is initiated by the receiver that states its availability to receive data through beacons. The sender is passively listening...... to the channel until it receives the beacon of interest. In this context, the dissertation begins with an in-depth survey of all the receiverinitiated MAC protocols and presents their unique optimization features, which deal with several challenges of the link layer such as mitigation of the energy consumption......-efficient features that aim to adapt the consumed energy to match the harvested energy, distribute the load with respect to the harvested energy, decrease the overhead of the communication, address the requirements for collision avoidance, prioritize urgent traffic and secure the system against beacon replay attacks...

  14. Effective energy harvesting from a single electrode based triboelectric nanogenerator

    Science.gov (United States)

    Kaur, Navjot; Bahadur, Jitendra; Panwar, Vinay; Singh, Pushpendra; Rathi, Keerti; Pal, Kaushik

    2016-12-01

    The arch-shaped single electrode based triboelectric nanogenerator (TENG) is fabricated using thin film of reduced graphene oxide nanoribbons (rGONRs) with polyvinylidene fluoride (PVDF) polymer used as binder to effectively convert mechanical energy into electrical energy. The incorporation of rGONRs in PVDF polymer enhances average surface roughness of rGONRs/PVDF thin film. With the combination of the enhancement of average roughness and production of functional groups, which indicate improve charge storage capacity of prepared film. Furthermore, the redox peaks obtained through cyclic voltammetry were identified more in rGONRs/PVDF composite in comparison to pristine rGONRs to confirm charge transfer capability of film. Herein, the output performance was discussed experimentally as well as theoretically, maximum voltage was obtained to be 0.35 V. The newly designed TENG to harvest mechanical energy and opens up many new avenues of research in the energy harvesting applications.

  15. Microstructured energy harvesters for energy autonomous sensors; Mikrostrukturierte Energiewandler fuer energieautonome Sensoren

    Energy Technology Data Exchange (ETDEWEB)

    Hohlfeld, Dennis; Kamel, Talal; Altena, Geert; Su, Jiale; Elfrink, Rene; Vullers, Ruud; Schaijk, Rob van [Holst Centre/IMEC, Eindhoven (Netherlands)

    2009-07-01

    This work presents microstructured energy harvesters for powering autonomous sensors. Vibrational devices either employ the piezoelectric or electrostatic effect for energy conversion with operating frequencies from 100 to 1000 Hz. We present a wireless energy autonomous sensor system, which transmits temperature measurements every 15 seconds powered by a vibrational energy harvester. Micromachined thermocouples are considered as a cost-effective breakthrough solution for energy harvesters working at low thermal gradients and weak heat flows, typical for e.g. human body heat generation. (orig.)

  16. Electret transducer for vibration-based energy harvesting

    Energy Technology Data Exchange (ETDEWEB)

    Hillenbrand, J., E-mail: j.hillenbrand@nt.tu-darmstadt.de; Sessler, G. M. [Institute for Telecommunications Technology, Technische Universität Darmstadt, Merckstr. 25, 64283 Darmstadt (Germany); Pondrom, P. [Institute for Telecommunications Technology, Technische Universität Darmstadt, Merckstr. 25, 64283 Darmstadt (Germany); System Reliability and Machine Acoustics SzM, Technische Universität Darmstadt, Magdalenenstr. 4, 64289 Darmstadt (Germany)

    2015-05-04

    Vibration-based electret energy harvesters with soft cellular spacer rings are presented. These harvesters are closely related to recently introduced electret accelerometers; however, their development targets are partially differing. Various harvesters with seismic masses from 8 to 23 g and surface potentials in the 500 V regime were built and characterized and powers of up to 8 μW at about 2 kHz and an acceleration of 1 g were measured. An analytical model is presented which, for instance, allows the calculation of the frequency response of the power output into a given load resistance. Finally, experimental and calculated results are compared.

  17. Piezoelectric energy harvesting from traffic-induced bridge vibrations

    Science.gov (United States)

    Peigney, Michaël; Siegert, Dominique

    2013-09-01

    This paper focuses on energy harvesting from traffic-induced vibrations in bridges. Using a pre-stressed concrete highway bridge as a case study, in situ vibration measurements are presented and analysed. From these results, a prototype of a cantilever piezoelectric harvester is designed, tested and modelled. Even though the considered bridge vibrations are characterized by small amplitude and a low frequency (i.e. below 15 Hz), it is shown that mean power of the order of 0.03 mW can be produced, with a controlled voltage between 1.8 and 3.6 V. A simple model is proposed for theoretical prediction of the delivered power in terms of traffic intensity. This model shows good agreement with the experimental results and leads to a simple but effective design rule for piezoelectric harvesters to be used on bridges.

  18. Light-harvesting materials: Soft support for energy conversion

    Energy Technology Data Exchange (ETDEWEB)

    Stolley, Ryan M.; Helm, Monte L.

    2014-11-10

    To convert solar energy into viable fuel sources, coupling light-harvesting materials to catalysts is a critical challenge. Now, coupling between an organic supramolecular hydrogel and a non precious metal catalyst has been demonstrated to be effective for photocatalytic H2 production. Ryan M. Stolley and Monte L. Helm are at Pacific Northwest National Laboratory (PNNL), Richland, WA, USA 99352. PNNL is operated by Battelle for the US Department of Energy. e-mail: Monte.Helm@pnnl.gov

  19. Piezoelectric Nanowires in Energy Harvesting Applications

    Directory of Open Access Journals (Sweden)

    Zhao Wang

    2015-01-01

    Full Text Available Recently, the nanogenerators which can convert the mechanical energy into electricity by using piezoelectric one-dimensional nanomaterials have exhibited great potential in microscale power supply and sensor systems. In this paper, we provided a comprehensive review of the research progress in the last eight years concerning the piezoelectric nanogenerators with different structures. The fundamental piezoelectric theory and typical piezoelectric materials are firstly reviewed. After that, the working mechanism, modeling, and structure design of piezoelectric nanogenerators were discussed. Then the recent progress of nanogenerators was reviewed in the structure point of views. Finally, we also discussed the potential application and future development of the piezoelectric nanogenerators.

  20. Fluttering energy harvesters in the wind: A review

    Science.gov (United States)

    McCarthy, J. M.; Watkins, S.; Deivasigamani, A.; John, S. J.

    2016-01-01

    The growing area of harvesting energy by aerodynamically induced flutter in a fluid stream is reviewed. Numerous approaches were found to understand, demonstrate and [sometimes] optimise harvester performance based on Movement-Induced or Extraneously Induced Excitation. Almost all research was conducted in smooth, unidirectional flow domains; either experimental or computational. The power outputs were found to be very low when compared to conventional wind turbines, but potential advantages could be lower noise levels. A consideration of the likely outdoor environment for fluttering harvesters revealed that the flow would be highly turbulent and having a mean flow angle in the horizontal plane that could approach a harvester from any direction. Whilst some multiple harvester systems in smooth, well-aligned flow found enhanced efficiency (due to beneficial wake interaction) this would require an invariant flow approach angle. It was concluded that further work needs to be performed to find a universally accepted metric for efficiency and to understand the effects of the realities of the outdoors, including the highly variable and turbulent flow conditions likely to be experienced.

  1. Do biomass harvesting guidelines influence herpetofauna following harvests of logging residues for renewable energy?.

    Science.gov (United States)

    Fritts, Sarah; Moorman, Christopher; Grodsky, Steven; Hazel, Dennis; Homyack, Jessica; Farrell, Chris; Castleberry, Steven

    2016-04-01

    Forests are a major supplier of renewable energy; however, gleaning logging residues for use as woody biomass feedstock could negatively alter habitat for species dependent on downed wood. Biomass Harvesting Guidelines (BHGs) recommend retaining a portion of woody biomass on the forest floor following harvest. Despite BHGs being developed to help ensure ecological sustainability, their contribution to biodiversity has not been evaluated experimentally at operational scales. We compared herpetofauanal evenness, diversity, and richness and abundance of Anaxyrus terrestris and Gastrophryne carolinensis among six treatments that varied in volume and spatial arrangement of woody biomass retained after clearcutting loblolly pine (Pinus taeda) plantations in North Carolina, USA (n = 4), 2011-2014 and Georgia (n = 4), USA 2011-2013. Treatments were: (1) biomass harvest with no BHGs, (2) 15% retention with biomass clustered, (3) 15% retention with biomass dispersed, (4) 30% retention with biomass clustered, (5) 30% retention with biomass dispersed, and (6) no biomass harvest. We captured individuals with drift fence arrays and compared evenness, diversity, and richness metrics among treatments with repeated-measure, linear mixed-effects models. We determined predictors of A. terrestris and G. carolinensis abundances using a priori candidate N-mixture models with woody biomass volume, vegetation structure, and groundcover composition as covariates. We had 206 captures of 25 reptile species and 8710 captures of 17 amphibian species during 53690 trap nights. Herpetofauna diversity, evenness, and richness were similar among treatments. A. terrestris abundance was negatively related to volume of retained woody biomass in treatment units in North Carolina in 2013. G. carolinensis abundance was positively related with volume of retained woody debris in treatment units in Georgia in 2012. Other relationships between A. terrestris and G. carolinensis abundances and habitat metrics

  2. Electrodynamic energy harvester for electrical transformer's temperature monitoring system

    Indian Academy of Sciences (India)

    Farid Khan; Shadman Razzaq

    2015-10-01

    The development of an electrodynamic energy harvester (EDEH) for operating a wireless temperature monitoring system for electrical transformer is reported in this work. Analytical modeling, fabrication and characterization of EDEH prototype are performed. The developed EDEH consists of a mild steel core, a wound copper coil and Teflon housing. COMSOL Multiphysics software is used to optimize the design of the harvester. The split-cylindrical design of the developed EDEH permitted the harvester to be wrapped around the output power cable of the electrical transformer without shutting-off the power or disconnecting the power cable. From the electrical transformer, at current levels of 27, 72 and 155 A in the main power line, the energy harvester produced maximum RMS load voltages of 0.356, 1.09 and 2.58 V respectively, when connected to 100 load resistance. However, at matching impedance of 24 (resistance of the coil), the EDEH produced the maximum power levels of 2.99, 19.66 and 112.03 mW for a cable currents of 27, 72 and 155 A respectively. The simulation results of the devised analytical model of the harvester are in good agreement with the experimental results. Moreover, at a cable current of 93 A, when the harvester is connected to the rectifying circuit, the optimum impedance shifted to 185 and the maximum power of 19 mW is generated at that load. The reduction in power generation is attributed to the power consumption of the rectifying circuit. When the rectified DC voltage is used to charge a 3.8 V, Nickel–Cadmium (Ni–Cd) rechargeable battery, it took 3 h to completely charge the battery from 1 to 3.85 V. With the charged battery a wireless temperature sensor node is successfully operated for monitoring the temperature of the electrical transformer.

  3. Structural Optimization of Triboelectric Nanogenerator for Harvesting Water Wave Energy.

    Science.gov (United States)

    Jiang, Tao; Zhang, Li Min; Chen, Xiangyu; Han, Chang Bao; Tang, Wei; Zhang, Chi; Xu, Liang; Wang, Zhong Lin

    2015-12-22

    Ocean waves are one of the most abundant energy sources on earth, but harvesting such energy is rather challenging due to various limitations of current technologies. Recently, networks formed by triboelectric nanogenerator (TENG) have been proposed as a promising technology for harvesting water wave energy. In this work, a basic unit for the TENG network was studied and optimized, which has a box structure composed of walls made of TENG composed of a wavy-structured Cu-Kapton-Cu film and two FEP thin films, with a metal ball enclosed inside. By combination of the theoretical calculations and experimental studies, the output performances of the TENG unit were investigated for various structural parameters, such as the size, mass, or number of the metal balls. From the viewpoint of theory, the output characteristics of TENG during its collision with the ball were numerically calculated by the finite element method and interpolation method, and there exists an optimum ball size or mass to reach maximized output power and electric energy. Moreover, the theoretical results were well verified by the experimental tests. The present work could provide guidance for structural optimization of wavy-structured TENGs for effectively harvesting water wave energy toward the dream of large-scale blue energy.

  4. Nanostructured Thermoelectric Oxides for Energy Harvesting Applications

    KAUST Repository

    Abutaha, Anas I.

    2015-11-24

    As the world strives to adapt to the increasing demand for electrical power, sustainable energy sources are attracting significant interest. Around 60% of energy utilized in the world is wasted as heat. Different industrial processes, home heating, and exhausts in cars, all generate a huge amount of unused waste heat. With such a huge potential, there is also significant interest in discovering inexpensive technologies for power generation from waste heat. As a result, thermoelectric materials have become important for many renewable energy research programs. While significant advancements have been done in improving the thermoelectric properties of the conventional heavy-element based materials (such as Bi2Te3 and PbTe), high-temperature applications of thermoelectrics are still limited to one materials system, namely SiGe, since the traditional thermoelectric materials degrade and oxidize at high temperature. Therefore, oxide thermoelectrics emerge as a promising class of materials since they can operate athigher temperatures and in harsher environments compared to non-oxide thermoelectrics. Furthermore, oxides are abundant and friendly to the environment. Among oxides, crystalline SrTiO3 and ZnO are promising thermoelectric materials. The main objective of this work is therefore to pursue focused investigations of SrTiO3 and ZnO thin films and superlattices grown by pulsed laser deposition (PLD), with the goal of optimizing their thermoelectric properties by following different strategies. First, the effect of laser fluence on the thermoelectric properties of La doped epitaxial SrTiO3 films is discussed. Films grown at higher laser fluences exhibit better thermoelectric performance. Second, the role of crystal orientation in determining the thermoelectric properties of epitaxial Al doped ZnO (AZO) films is explained. Vertically aligned (c-axis) AZO films have superior thermoelectric properties compared to other films with different crystal orientations. Third

  5. Novel composite piezoelectric material for energy harvesting applications

    Science.gov (United States)

    Janusas, Giedrius; Guobiene, Asta; Palevicius, Arvydas; Prosycevas, Igoris; Ponelyte, Sigita; Baltrusaitis, Valentinas; Sakalys, Rokas

    2015-04-01

    Past few decades were concentrated on researches related to effective energy harvesting applied in modern technologies, MEMS or MOEMS systems. There are many methods for harvesting energy as, for example, usage of electromagnetic devices, but most dramatic changes were noticed in the usage of piezoelectric materials in small scale devices. Major limitation faced was too small generated power by piezoelectric materials or high resonant frequencies of such smallscale harvesters. In this research, novel composite piezoelectric material was created by mixing PZT powder with 20% solution of polyvinyl butyral in benzyl alcohol. Obtained paste was screen printed on copper foil using 325 mesh stainless steel screen and dried for 30 min at 100 °C. Polyvinyl butyral ensures good adhesion and flexibility of a new material at the conditions that requires strong binding. Five types of a composite piezoelectric material with different concentrations of PZT (40%, 50%, 60%, 70% and 80 %) were produced. As the results showed, these harvesters were able to transform mechanical strain energy into electric potential and, v.v. In experimental setup, electromagnetic shaker was used to excite energy harvester that is fixed in the custom-built clamp, while generated electric potential were registered with USB oscilloscope PICO 3424. The designed devices generate up to 80 μV at 50 Hz excitation. This property can be applied to power microsystem devices or to use them in portable electronics and wireless sensors. However, the main advantage of the created composite piezoelectric material is possibility to apply it on any uniform or nonuniform vibrating surface and to transform low frequency vibrations into electricity.

  6. Triboelectric-thermoelectric hybrid nanogenerator for harvesting frictional energy

    Science.gov (United States)

    Kim, Min-Ki; Kim, Myoung-Soo; Jo, Sung-Eun; Kim, Yong-Jun

    2016-12-01

    The triboelectric nanogenerator, an energy harvesting device that converts external kinetic energy into electrical energy through using a nano-structured triboelectric material, is well known as an energy harvester with a simple structure and high output voltage. However, triboelectric nanogenerators also inevitably generate heat resulting from the friction that arises from their inherent sliding motions. In this paper, we present a hybrid nanogenerator, which integrates a triboelectric generator and a thermoelectric generator (TEG) for harvesting both the kinetic friction energy and the heat energy that would otherwise be wasted. The triboelectric part consists of a polytetrafluoroethylene (PTFE) film with nano-structures and a movable aluminum panel. The thermoelectric part is attached to the bottom of the PTFE film by an adhesive phase change material layer. We confirmed that the hybrid nanogenerator can generate an output power that is higher than that generated by a single triboelectric nanogenerator or a TEG. The hybrid nanogenerator was capable of producing a power density of 14.98 mW cm-2. The output power, produced from a sliding motion of 12 cm s-1, was capable of instantaneously lighting up 100 commercial LED bulbs. The hybrid nanogenerator can charge a 47 μF capacitor at a charging rate of 7.0 mV s-1, which is 13.3% faster than a single triboelectric generator. Furthermore, the efficiency of the device was significantly improved by the addition of a heat source. This hybrid energy harvester does not require any difficult fabrication steps, relative to existing triboelectric nanogenerators. The present study addresses a method for increasing the efficiency while solving other problems associated with triboelectric nanogenerators.

  7. Comparison of Energy Harvesting Systems for Wireless Sensor Networks

    Institute of Scientific and Technical Information of China (English)

    James M. Gilbert; Farooq Balouchi

    2008-01-01

    Wireless sensor networks (WSNs) offer an attractive solution to many environmental, security, and process monitoring problems. However, one barrier to their fuller adoption is the need to supply electrical power over extended periods of time without the need for dedicated wiring. Energy harvesting provides a potential solution to this problem in many applications. This paper reviews the characteristics and energy requirements of typical sensor network nodes, assesses a range of potential ambient energy sources, and outlines the characteristics of a wide range of energy conversion devices. It then proposes a method to compare these diverse sources and conversion mechanisms in terms of their normalised power density.

  8. Using DNA nanostructures to harvest light and create energy transfer and harvesting systems

    Science.gov (United States)

    Díaz, Sebastián. A.; Buckhout-White, Susan; Brown, Carl W.; Samanta, Anirban; Klein, William P.; Ancona, Mario G.; Dwyer, Chris L.; Goldman, Ellen R.; Melinger, Joseph S.; Cunningham, Paul D.; Spillmann, Chris M.; Medintz, Igor L.

    2016-12-01

    DNA is a biocompatible scaffold that allows for the design of a variety of nanostructures, from straightforward double stranded DNA to more complex DNA origami and 3-D structures. By modifying the structures, with dyes, nanoparticles, or enzymes, they can be used to create light harvesting and energy transfer systems. We have focused on using Förster resonance energy transfer (FRET) between organic fluorophores separated with nanometer precision based on the DNAs defined positioning. Using FRET theory we can control the direction of the energy flow and optimize the design parameters to increase the systems efficiency. The design parameters include fluorophore selection, separation, number, and orientation among others. Additionally the use of bioluminescence resonance energy transfer (BRET) allowed the use of chemical energy, as opposed to photonic, to activate the systems. Here we discuss a variety of systems, such as the longest reported DNA-based molecular photonic wires (> 30 nm), dendrimeric light harvesting systems, and semiconductor nanocrystals integrated systems where they act as both scaffold and antennae for the original excitation. Using a variety of techniques, a comparison of different types of structures as well as heterogeneous vs. homogenous FRET was realized.

  9. Optimization of Vibration Energy Harvesting on Wind-Spear

    Directory of Open Access Journals (Sweden)

    S. Nagakalyan, B. Raghu Kumar, K. V. Abhilash

    2013-07-01

    Full Text Available his analysis shows that, the coordinated Switch Harvesting on Inductor topology is higher in output power at small vibrations at 1 Hz. The recital of the topology at a frequency of 1 Hz and output power levels around 10 µW was found to positive and negative with the peak detection control circuit performance. The sampleshowed to increase the output power by a factor of two, compared to the standard full bridge rectifier, but when accounting for the control circuit power consumption of 13.2µW the gained output power was lost. The control circuit showed to be more of a limiting factor than expected and a set of requirements for a new control circuit was made. At higher energy levels the sample is expected to increase the output energy by up to 10 times and to extend the range of feasible low frequency energy harvesting sources and applications.

  10. Optimum Transmission Policies for Battery Limited Energy Harvesting Nodes

    CERN Document Server

    Tutuncuoglu, Kaya

    2010-01-01

    Wireless networks with energy harvesting battery powered nodes are quickly emerging as a viable option for future wireless networks with extended lifetime. Equally important to their counterpart in the design of energy harvesting radios are the design principles that this new networking paradigm calls for. In particular, unlike wireless networks considered up to date, the energy replenishment process and the storage constraints of the rechargeable batteries need to be taken into account in designing efficient transmission strategies. In this work, we consider such transmission policies for rechargeable nodes, and identify the optimum solution for two related problems. Specifically, the transmission policy that maximizes the short term throughput, i.e., the amount of data transmitted in a finite time horizon is found. In addition, we show the relation of this optimization problem to another, namely, the minimization of the transmission completion time for a given amount of data, and solve that as well. The tra...

  11. Optimal Energy Transfer in Light-Harvesting Systems

    Directory of Open Access Journals (Sweden)

    Lipeng Chen

    2015-08-01

    Full Text Available Photosynthesis is one of the most essential biological processes in which specialized pigment-protein complexes absorb solar photons, and with a remarkably high efficiency, guide the photo-induced excitation energy toward the reaction center to subsequently trigger its conversion to chemical energy. In this work, we review the principles of optimal energy transfer in various natural and artificial light harvesting systems. We begin by presenting the guiding principles for optimizing the energy transfer efficiency in systems connected to dissipative environments, with particular attention paid to the potential role of quantum coherence in light harvesting systems. We will comment briefly on photo-protective mechanisms in natural systems that ensure optimal functionality under varying ambient conditions. For completeness, we will also present an overview of the charge separation and electron transfer pathways in reaction centers. Finally, recent theoretical and experimental progress on excitation energy transfer, charge separation, and charge transport in artificial light harvesting systems is delineated, with organic solar cells taken as prime examples.

  12. Performance Analysis of a Magnetorheological Damper with Energy Harvesting Ability

    Directory of Open Access Journals (Sweden)

    Guoliang Hu

    2016-01-01

    Full Text Available A magnetorheological (MR damper with energy harvesting ability was proposed based on electromagnetic induction (EMI principle. The energy harvesting part was composed of a permanent magnet array and inducing coils which move vertically. This device could act as a linear power generator when the external excitation was applied, and the kinetic energy could be converted into electrical energy due to the relative linear motion between the magnets array and the inducing coils. Finite element models of both the MR damper part and the linear power generator part were built up separately to address the magnetic flux distributions, the magnetic flux densities, and the power generating efficiency using ANSYS software. The experimental tests were carried out to evaluate the damping performance and power generating efficiency. The results show that the proposed MR damper can produce approximately 750 N damping forces at the current of 0.6 A, and the energy harvesting device can generate about 1.0 V DC voltage at 0.06 m·s−1 excitation.

  13. Optimal Energy Transfer in Light-Harvesting Systems.

    Science.gov (United States)

    Chen, Lipeng; Shenai, Prathamesh; Zheng, Fulu; Somoza, Alejandro; Zhao, Yang

    2015-08-20

    Photosynthesis is one of the most essential biological processes in which specialized pigment-protein complexes absorb solar photons, and with a remarkably high efficiency, guide the photo-induced excitation energy toward the reaction center to subsequently trigger its conversion to chemical energy. In this work, we review the principles of optimal energy transfer in various natural and artificial light harvesting systems. We begin by presenting the guiding principles for optimizing the energy transfer efficiency in systems connected to dissipative environments, with particular attention paid to the potential role of quantum coherence in light harvesting systems. We will comment briefly on photo-protective mechanisms in natural systems that ensure optimal functionality under varying ambient conditions. For completeness, we will also present an overview of the charge separation and electron transfer pathways in reaction centers. Finally, recent theoretical and experimental progress on excitation energy transfer, charge separation, and charge transport in artificial light harvesting systems is delineated, with organic solar cells taken as prime examples.

  14. Thermomechanic micro-generators for energy harvesting

    Energy Technology Data Exchange (ETDEWEB)

    Huesgen, Till

    2010-07-01

    This work, in contrast, focuses on the development of a novel thermomechanic generator based on a dynamic micro engine. The engine is fabricated on a chip-scale in silicon technology and is unique regarding its size and properties. A closed engine chamber, filled with a working fluid, performs a reciprocating motion between a heat source and a heat sink. Thereby, the engine operates passively hence it is self starting and the operation frequency depends on the applied temperature difference. Primary goals of this work are the design of the engine and an experimental proof-of-concent. A hybrid model composed of a FEM simulation for the membrane mechanics, analytical calculations of the thermodynamic cycle, and a thermal network model, allows to theoretically investigate the engine performance. The relevant benchmarks are the operation frequency, mechanical output power and the thermal resistance of the engine. Using this model, an exemplary optimization of the engine geometry is conducted with respect to a high efficiency. In this case, a theoretical optimum of 28.3 x 10{sup -4}% is found for the thermomechanic energy conversion. The experimental part focuses on the fabrication and characterization of a not optimized demonstrator engine. Two different types of working fluid are applied, either air or an organic coolant. The maximum measured operation frequency is 1.2 Hz at 100 K temperature difference for the air-filled engine and 0.75 Hy at 37 K temperature difference for the engine filled with the organic coolant. A maximum velocity of 0.061 m/sec and -0.031 m/sec is measured for the upward and downward motion. These experimental data yield a maximum mechanical output power of 0.5 {mu}W for the air-filled engine and 0.26 {mu}W for the engine filled with the organic coolant. The integration of an electric generator provides a further task. Two fundamentally different approaches have been investigated. The first approach is based on an electromagnetic conversion of

  15. Triplet Energy Transport in Platinum-Acetylide Light Harvesting Arrays.

    Science.gov (United States)

    Chen, Zhuo; Hsu, Hsien-Yi; Arca, Mert; Schanze, Kirk S

    2015-06-18

    Light harvesting and triplet energy transport is investigated in chromophore-functionalized polystyrene polymers featuring light harvesting and energy acceptor chromophores (traps) at varying loading. The series of precision polymers was constructed via reversible addition-fragmentation transfer polymerization and functionalized with platinum acetylide triplet chromophores by using an azide-alkyne "click" reaction. The polymers have narrow polydispersity and degree of polymerization ∼60. The chromophores have the general structure, trans-[-R-C6H4-C≡C-Pt(PBu3)2-C≡C-Ar], where R is the attachment point to the polystyrene backbone and Ar is either -C6H4-C≡C-Ph or -pyrenyl (PE2-Pt and Py-Pt, respectively, with triplet energies of 2.35 and 1.88 eV). The polychromophores contain mainly the high-energy PE2-Pt units (light absorber and energy donor), with randomly distributed Py-Pt units (3-20% loading, energy acceptor). Photophysical methods are used to study the dynamics and efficiency of energy transport from the PE2-Pt to Py-Pt units in the polychromophores. The energy transfer efficiency is >90% for copolymers that contain 5% of the Py-Pt acceptor units. Time-resolved phosphorescence measurements combined with Monte Carlo exciton dynamics simulations suggest that the mechanism of exciton transport is exchange energy transfer hopping between PE2-Pt units.

  16. Electroelastodynamics of flexoelectric energy conversion and harvesting in elastic dielectrics

    Science.gov (United States)

    Moura, Adriane G.; Erturk, Alper

    2017-02-01

    Flexoelectricity is the generation of electric polarization by the application of a non-uniform mechanical strain field, i.e., a strain gradient. This phenomenon is exhibited by all elastic dielectrics, but is expected to be significant only at very small scales. Energy harvesting is a potential future application area of flexoelectricity to enable next-generation ultra-low-power MEMS/NEMS devices by converting ambient vibrations into electricity. In this paper, an electroelastodynamic framework is presented and analyzed for flexoelectric energy harvesting from strain gradient fluctuations in centrosymmetric dielectrics, by accounting for the presence of a finite electrical load across the surface electrodes as well as two-way electromechanical coupling, and capturing the size effect. The flexoelectric energy harvester model is based on the Euler-Bernoulli beam theory and it assumes the main source of polarization to be static bulk flexoelectricity. Following recent efforts on the converse flexoelectric effect in finite samples, the proposed model properly accounts for thermodynamically consistent, symmetric direct and converse coupling terms. The transverse mode flexoelectric coupling coefficient (k) is obtained analytically as a direct measure of energy conversion; its dependence on the cantilever thickness and a material Figure of Merit (FoM) is shown. Size effects are further demonstrated by simulations of the electromechanical frequency response for a Strontium Titanate (STO) energy harvester at different geometric scales. It is obtained that the flexoelectric coupling coefficient of an STO cantilever for the fundamental bending mode increases from k ≈3.5 ×10-7 to k ≈0.33 as the thickness is reduced from mm- to nm-level. A critique of the experimentally identified large flexoelectric coefficient for Barium Strontium Titanate (BST) from the literature is also given with a coupling coefficient perspective.

  17. Antenna Performance Improvement Techniques for Energy Harvesting: A Review Study

    Directory of Open Access Journals (Sweden)

    Raed Abdulkareem Abdulhasan

    2017-01-01

    Full Text Available The energy harvesting is defined as using energy that is available within the environment to increase the efficiency of any application. Moreover, this method is recognized as a useful way to break down the limitation of battery power for wireless devices. In this paper, several antenna designs of energy harvesting are introduced. The improved results are summarized as a 2×2 patch array antenna realizes improved efficiency by 3.9 times higher than the single patch antenna. The antenna has enhanced the bandwidth of 22.5 MHz after load two slots on the patch. The solar cell antenna is allowing harvesting energy during daylight. A couple of E-patches antennas have increased the bandwidth of 33% and the directivity up to 20 dBi. The received power can be improved by 1.2-1.4 times when using the dual port on pixel antenna. Complementary split ring resonator and substrate integrated waveguide are utilized cavity-backed feeding on a fractal patch antenna to enhance the bandwidth around 5.1%. Moreover, adding a rectifier circuit to an antenna converts the reserved RF-signal to DC power, and then duplicated the input voltage up to sum the total number of rectifier circuit stages. Therefore, the advantages and disadvantages of each antenna depend on the technique which used in design.

  18. Roles of the Excitation in Harvesting Energy from Vibrations.

    Directory of Open Access Journals (Sweden)

    Hui Zhang

    Full Text Available The study investigated the role of excitation in energy harvesting applications. While the energy ultimately comes from the excitation, it was shown that the excitation may not always behave as a source. When the device characteristics do not perfectly match the excitation, the excitation alternately behaves as a source and a sink. The extent to which the excitation behaves as a sink determines the energy harvesting efficiency. Such contradictory roles were shown to be dictated by a generalized phase defined as the instantaneous phase angle between the velocity of the device and the excitation. An inductive prototype device with a diamagnetically levitated seismic mass was proposed to take advantage of the well established phase changing mechanism of vibro-impact to achieve a broader device bandwidth. Results suggest that the vibro-impact can generate an instantaneous, significant phase shift in response velocity that switches the role of the excitation. If introduced properly outside the resonance zone it could dramatically increase the energy harvesting efficiency.

  19. Roles of the Excitation in Harvesting Energy from Vibrations.

    Science.gov (United States)

    Zhang, Hui; Ma, Tianwei

    2015-01-01

    The study investigated the role of excitation in energy harvesting applications. While the energy ultimately comes from the excitation, it was shown that the excitation may not always behave as a source. When the device characteristics do not perfectly match the excitation, the excitation alternately behaves as a source and a sink. The extent to which the excitation behaves as a sink determines the energy harvesting efficiency. Such contradictory roles were shown to be dictated by a generalized phase defined as the instantaneous phase angle between the velocity of the device and the excitation. An inductive prototype device with a diamagnetically levitated seismic mass was proposed to take advantage of the well established phase changing mechanism of vibro-impact to achieve a broader device bandwidth. Results suggest that the vibro-impact can generate an instantaneous, significant phase shift in response velocity that switches the role of the excitation. If introduced properly outside the resonance zone it could dramatically increase the energy harvesting efficiency.

  20. Advanced model for fast assessment of piezoelectric micro energy harvesters

    Science.gov (United States)

    Ardito, Raffaele; Corigliano, Alberto; Gafforelli, Giacomo; Valzasina, Carlo; Procopio, Francesco; Zafalon, Roberto

    2016-04-01

    The purpose of this work is to present recent advances in modelling and design of piezoelectric energy harvesters, in the framework of Micro-Electro-Mechanical Systems (MEMS). More specifically, the case of inertial energy harvesting is considered, in the sense that the kinetic energy due to environmental vibration is transformed into electrical energy by means of piezoelectric transduction. The execution of numerical analyses is greatly important in order to predict the actual behaviour of MEMS devices and to carry out the optimization process. In the common practice, the results are obtained by means of burdensome 3D Finite Element Analyses (FEA). The case of beams could be treated by applying 1D models, which can enormously reduce the computational burden with obvious benefits in the case of repeated analyses. Unfortunately, the presence of piezoelectric coupling may entail some serious issues in view of its intrinsically three-dimensional behaviour. In this paper, a refined, yet simple, model is proposed with the objective of retaining the Euler-Bernoulli beam model, with the inclusion of effects connected to the actual three-dimensional shape of the device. The proposed model is adopted to evaluate the performances of realistic harvesters, both in the case of harmonic excitation and for impulsive loads.

  1. Advanced model for fast assessment of piezoelectric micro energy harvesters

    Directory of Open Access Journals (Sweden)

    Raffaele eArdito

    2016-04-01

    Full Text Available The purpose of this work is to present recent advances in modelling and design of piezoelectric energy harvesters, in the framework of Micro-Electro-Mechanical Systems (MEMS. More specifically, the case of inertial energy harvesting is considered, in the sense that the kinetic energy due to environmental vibration is transformed into electrical energy by means of piezoelectric transduction. The execution of numerical analyses is greatly important in order to predict the actual behaviour of MEMS devices and to carry out the optimization process. In the common practice, the results are obtained by means of burdensome 3D Finite Element Analyses (FEA.The case of beams could be treated by applying 1D models, which can enormously reduce the computational burden with obvious benefits in the case of repeated analyses. Unfortunately, the presence of piezoelectric coupling may entail some serious issues in view of its intrinsically three-dimensional behaviour. In this paper, a refined, yet simple, model is proposed with the objective of retaining the Euler-Bernoulli beam model, with the inclusion of effects connected to the actual three-dimensional shape of the device. The proposed model is adopted to evaluate the performances of realistic harvesters, both in the case of harmonic excitation and for impulsive loads.

  2. Energy harvesting “3-D knitted spacer” based piezoelectric textiles

    Science.gov (United States)

    Anand, S.; Soin, N.; Shah, T. H.; Siores, E.

    2016-07-01

    The piezoelectric effect in Poly(vinylidene fluoride), PVDF, was discovered over four decades ago and since then, significant work has been carried out aiming at the production of high p-phase fibres and their integration into fabric structures for energy harvesting. However, little work has been done in the area of production of “true piezoelectric fabric structures” based on flexible polymeric materials such as PVDF. In this work, we demonstrate “3-D knitted spacer” technology based all-fibre piezoelectric fabrics as power generators and energy harvesters. The knitted single-structure piezoelectric generator consists of high p-phase (~80%) piezoelectric PVDF monofilaments as the spacer yarn interconnected between silver (Ag) coated polyamide multifilament yarn layers acting as the top and bottom electrodes. The novel and unique textile structure provides an output power density in the range of 1.105.10 gWcm-2 at applied impact pressures in the range of 0.02-0.10 MPa, thus providing significantly higher power outputs and efficiencies over the existing 2-D woven and nonwoven piezoelectric structures. The high energy efficiency, mechanical durability and comfort of the soft, flexible and all-fibre based power generator is highly attractive for a variety of potential applications such as wearable electronic systems and energy harvesters charged from ambient environment or by human movement.

  3. A plastic-composite-plastic structure high performance flexible energy harvester based on PIN-PMN-PT single crystal/epoxy 2-2 composite

    Science.gov (United States)

    Zeng, Zhou; Gai, Linlin; Wang, Xian; Lin, Di; Wang, Sheng; Luo, Haosu; Wang, Dong

    2017-03-01

    We present a high performance flexible piezoelectric energy harvester constituted by a Pb(In1/2Nb1/2)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3 (PIN-PMN-PT) single crystal/epoxy 2-2 composite flake, a polyethylene terephthalate (PET) substrate, and a PET cover, which is capable of harvesting energy from biomechanical movements. Electrical properties of the device under different epoxy volume fractions, load resistances, and strains are studied systematically. Both theoretical and experimental results show that the plastic-composite-plastic structure contributes to the flexibility of the device, and a high performance bulk PIN-PMN-PT single crystal (a thickness of 50 μm) results in its high electrical output. At a low excitation frequency of 4.2 Hz, the optimal flexible energy harvester (with ve = 21%) can generate a peak voltage of 12.9 V and a maximum power density of 0.28 mW/cm3 under a bending radius of 10.5 mm, and maintain its performance after 40 000 bending-unbending cycles. High flexibility and excellent electrical output at low operational frequency demonstrate the promise of the device in biomechanical motion energy harvesting for wireless and portable low-power electronics.

  4. Photochromic Electret: A New Tool for Light Energy Harvesting.

    Science.gov (United States)

    Castagna, Rossella; Garbugli, Michele; Bianco, Andrea; Perissinotto, Stefano; Pariani, Giorgio; Bertarelli, Chiara; Lanzani, Guglielmo

    2012-01-05

    In this paper, a photochromic electret for light energy harvesting is proposed and discussed. Such electret directly converts the photon energy into electric energy thanks to a polarization modulation caused by the photochromic reaction, which leads to a change in dipole moment. Theoretical concepts on which the photochromic electret is based are considered with an estimation of the effectiveness as a function of material properties. Finally, an electret based on a photochromic diarylethene is shown with the photoelectric characterization as a proof of concept device.

  5. Solar Energy: Progress and Design Concerns of Nanostructured Solar Energy Harvesting Devices (Small 19/2016).

    Science.gov (United States)

    Leung, Siu-Fung; Zhang, Qianpeng; Tavakoli, Mohammad Mahdi; He, Jin; Mo, Xiaoliang; Fan, Zhiyong

    2016-05-01

    Nanoengineered materials and structures can harvest light efficiently for photovoltaic applications. Device structure design optimization and material property improvement are equally important for high performance. On page 2536, X. Mo, Z. Fan, and co-workers summarize the design guidelines of solar energy harvesting devices to assist with a better understanding of device physics.

  6. Piezoelectric energy harvester having planform-tapered interdigitated beams

    Science.gov (United States)

    Kellogg, Rick A.; Sumali, Hartono

    2011-05-24

    Embodiments of energy harvesters have a plurality of piezoelectric planform-tapered, interdigitated cantilevered beams anchored to a common frame. The plurality of beams can be arranged as two or more sets of beams with each set sharing a common sense mass affixed to their free ends. Each set thus defined being capable of motion independent of any other set of beams. Each beam can comprise a unimorph or bimorph piezoelectric configuration bonded to a conductive or non-conductive supporting layer and provided with electrical contacts to the active piezoelectric elements for collecting strain induced charge (i.e. energy). The beams are planform tapered along the entirety or a portion of their length thereby increasing the effective stress level and power output of each piezoelectric element, and are interdigitated by sets to increase the power output per unit volume of a harvester thus produced.

  7. Three-terminal energy harvester with coupled quantum dots.

    Science.gov (United States)

    Thierschmann, Holger; Sánchez, Rafael; Sothmann, Björn; Arnold, Fabian; Heyn, Christian; Hansen, Wolfgang; Buhmann, Hartmut; Molenkamp, Laurens W

    2015-10-01

    Rectification of thermal fluctuations in mesoscopic conductors is the key idea behind recent attempts to build nanoscale thermoelectric energy harvesters to convert heat into useful electric power. So far, most concepts have made use of the Seebeck effect in a two-terminal geometry, where heat and charge are both carried by the same particles. Here, we experimentally demonstrate the working principle of a new kind of energy harvester, proposed recently, using two capacitively coupled quantum dots. We show that, due to the novel three-terminal design of our device, which spatially separates the heat reservoir from the conductor circuit, the directions of charge and heat flow become decoupled. This enables us to manipulate the direction of the generated charge current by means of external gate voltages while leaving the direction of heat flow unaffected. Our results pave the way for a new generation of multi-terminal nanoscale heat engines.

  8. Stacked and folded piezoelectrets for vibration-based energy harvesting

    Science.gov (United States)

    Sessler, G. M.; Pondrom, P.; Zhang, X.

    2016-08-01

    Vibration-based energy harvesting with piezoelectrets can be significantly improved by using multiple layers of these materials. In particular, folding or stacking of piezoelectrets or a combination of these methods results in increased power output of the energy harvesters. The possibilities of these procedures are explored, together with the effect of seismic mass, resonance frequency, and terminating resistance. It is found that with seismic masses of about 20 g and using radiation-crosslinked polypropylene (IXPP) as a piezoelectret, power outputs of up to 80 µW can be achieved for an acceleration of 1 g. Expected dependencies of generated power on frequency, folding and stacking parameters, in particular number of layers, and on seismic mass, are confirmed.

  9. A novel vibrational energy harvester with electric double layer electrets

    Science.gov (United States)

    Ono, S.; Miwa, K.; Iori, J.; Mitsuya, H.; Ishibashi, K.; Sano, C.; Toshiyoshi, H.; Fujita, H.

    2016-11-01

    We propose a new type of vibrational energy harvester with an electric double layer (EDL) electrets. Instead of using any external bias-voltage source or dielectric layer on top of the metal electrode to sustain EDL, we succeed to anchor the ions to polymer network to form the EDL electrets. By changing contact area between the EDL electrets and the electrode, large electric current is generated in the circuit. Owing to extremely large capacitance of the EDL electret, vibrational energy harvesters have the unique capability to leverage the high- density charge accumulation to the electrode and obtained current density becomes as high as 200 μA/cm2 with output voltage of 1V even with low frequency vibrations as low as 1 Hz.

  10. Energy harvesting from a backpack instrumented with piezoelectric shoulder straps

    Science.gov (United States)

    Granstrom, Jonathan; Feenstra, Joel; Sodano, Henry A.; Farinholt, Kevin

    2007-10-01

    Over the past few decades the use of portable and wearable electronics has grown steadily. These devices are becoming increasingly more powerful. However, the gains that have been made in the device performance have resulted in the need for significantly higher power to operate the electronics. This issue has been further complicated due to the stagnant growth of battery technology over the past decade. In order to increase the life of these electronics, researchers have begun investigating methods of generating energy from ambient sources such that the life of the electronics can be prolonged. Recent developments in the field have led to the design of a number of mechanisms that can be used to generate electrical energy, from a variety of sources including thermal, solar, strain, inertia, etc. Many of these energy sources are available for use with humans, but their use must be carefully considered such that parasitic effects that could disrupt the user's gait or endurance are avoided. These issues have arisen from previous attempts to integrate power harvesting mechanisms into a shoe such that the energy released during a heal strike could be harvested. This study develops a novel energy harvesting backpack that can generate electrical energy from the differential forces between the wearer and the pack. The goal of this system is to make the energy harvesting device transparent to the wearer such that his or her endurance and dexterity is not compromised. This will be accomplished by replacing the traditional strap of the backpack with one made of the piezoelectric polymer polyvinylidene fluoride (PVDF). Piezoelectric materials have a structure such that an applied electrical potential results in a mechanical strain. Conversely, an applied stress results in the generation of an electrical charge, which makes the material useful for power harvesting applications. PVDF is highly flexible and has a high strength, allowing it to effectively act as the load bearing

  11. Optimal Design of Piezoelectric Materials for Maximal Energy Harvesting

    Science.gov (United States)

    2015-06-01

    devices without access to other alternative power sources ( solar , wind, geothermal) • devices with access to vibrations or other mechanical...addition to solar and wind power genera- tion, service members could generate power with piezoelectric power generators fixed to personnel, equipment...motivation and relevant background of harvesting piezoelectric energy . In Chapter 2, we review a one-dimensional power generation model and study how to

  12. Waveform Optimization for SWIPT with Nonlinear Energy Harvester Modeling

    OpenAIRE

    Clerckx, Bruno

    2016-01-01

    Simultaneous Wireless Information and Power Transfer (SWIPT) has attracted significant attention in the communication community. The problem of waveform design for SWIPT has however never been addressed so far. In this paper, a novel SWIPT transceiver architecture is introduced relying on the superposition of multisine and OFDM waveforms at the transmitter and a power-splitter receiver equipped with an energy harvester and an information decoder capable of cancelling the multisine waveforms. ...

  13. Energy Harvesting Wireless Sensor Networks: Design and Modeling

    Directory of Open Access Journals (Sweden)

    Hussaini Habibu

    2014-11-01

    Full Text Available Wireless sensor nodes are usually deployed in not e asily accessible places to provide solution to a wi de range of application such as environmental, medical and structural monitoring. They are spatially distributed and as a result are usually powered fro m batteries. Due to the limitation in providing pow er with batteries, which must be manually replaced whe n they are depleted, and location constraints in wireless sensor network causes a major setback on p erformance and lifetime of WSNs. This difficulty in battery replacement and cost led to a growing inter est in energy harvesting. The current practice in e nergy harvesting for sensor networks is based on practica l and simulation approach. The evaluation and validation of the WSN systems is mostly done using simulation and practical implementation. Simulation is widely used especially for its great advantage in e valuating network systems. Its disadvantages such a s the long time taken to simulate and not being economic al as it implements data without proper analysis of all that is involved ,wasting useful resources cannot b e ignored. In most times, the energy scavenged is d irectly wired to the sensor nodes. We, therefore, argue tha t simulation – based and practical implementation o f WSN energy harvesting system should be further stre ngthened through mathematical analysis and design procedures. In this work, we designed and modeled t he energy harvesting system for wireless sensor nod es based on the input and output parameters of the ene rgy sources and sensor nodes. We also introduced th e use of supercapacitor as buffer and intermittent so urce for the sensor node. The model was further tes ted in a Matlab environment, and found to yield a very goo d approach for system design

  14. PDMS/PVA composite ferroelectret for improved energy harvesting performance

    Science.gov (United States)

    Shi, J.; Luo, Z.; Zhu, D.; Beeby, S. P.

    2016-11-01

    This paper address the PDMS ferroelectret discharge issue for improved long- term energy harvesting performance. The PDMS/PVA ferroelectret is fabricated using a 3D-printed plastic mould technology and a functional PVA composite layer is introduced. The PDMS/PVA composite ferroelectret achieved 80% piezoelectric coefficient d33 remaining, compared with 40% without the proposed layer over 72 hours. Further, the retained percentage of output voltage is about 73% over 72 hours.

  15. Energy harvesting technologies for wireless sensors in rotating environments

    OpenAIRE

    Häggström, Fredrik; Gustafsson, Jonas; Delsing, Jerker

    2014-01-01

    Using sensors to measure parameters of interest in rotating environments and communicating the measurements in real-time over wireless links, requires a reliable power source. In this paper, we have investigated the possibility to generate electric power locally by evaluating six different energy-harvesting technologies. The applicability of the technology is evaluated by several parameters that are important to the functionality in an industrial environment. All technologies are individually...

  16. Multiple Timescale Energy Scheduling for Wireless Communication with Energy Harvesting Devices

    Directory of Open Access Journals (Sweden)

    H. Xiao

    2012-09-01

    Full Text Available The primary challenge in wireless communication with energy harvesting devices is to efficiently utilize the harvesting energy such that the data packet transmission could be supported. This challenge stems from not only QoS requirement imposed by the wireless communication application, but also the energy harvesting dynamics and the limited battery capacity. Traditional solar predictable energy harvesting models are perturbed by prediction errors, which could deteriorate the energy management algorithms based on this models. To cope with these issues, we first propose in this paper a non-homogenous Markov chain model based on experimental data, which can accurately describe the solar energy harvesting process in contrast to traditional predictable energy models. Due to different timescale between the energy harvesting process and the wireless data transmission process, we propose a general framework of multiple timescale Markov decision process (MMDP model to formulate the joint energy scheduling and transmission control problem under different timescales. We then derive the optimal control policies via a joint dynamic programming and value iteration approach. Extensive simulations are carried out to study the performances of the proposed schemes.

  17. A novel inertial energy harvester using magnetic shape memory alloy

    Science.gov (United States)

    Askari Farsangi, Mohammad Amin; Sayyaadi, Hassan; Zakerzadeh, Mohammad Reza

    2016-10-01

    This paper studies the output voltage from a novel inertial energy harvester using magnetic shape memory alloys (MSMAs). The MSMA elements are attached to the root of a cantilever beam by means of two steps. In order to get electrical voltage, two coils are wound around the MSMAs and a shock load is applied to a tip mass at the end of the beam to have vibration in it. The beam vibration causes strain in the MSMAs along their longitudinal directions and as a result the magnetic flux alters in the coils. The change of magnetic flux in the surrounding coil produces an AC voltage. In order to predict the output voltage, the nonlinear governing equations of beam motion based on Euler-Bernoulli model and von Kármán theory are derived. A thermodynamics-based constitutive model is used to predict the nonlinear strain and magnetization response of the MSMAs. Also, the induced voltage during martensite variant reorientation in MSMAs is investigated with the help of Faraday’s law of induction. Finally, the effect of different parameters including bias magnetic field, pre-strain and number of MSMA elements are investigated in details. The results show that this novel energy harvester has the capability of using as an alternative to the current piezoelectric and magnetostrictive ones for harvesting energy from ambient vibration.

  18. Progress and Design Concerns of Nanostructured Solar Energy Harvesting Devices.

    Science.gov (United States)

    Leung, Siu-Fung; Zhang, Qianpeng; Tavakoli, Mohammad Mahdi; He, Jin; Mo, Xiaoliang; Fan, Zhiyong

    2016-05-01

    Integrating devices with nanostructures is considered a promising strategy to improve the performance of solar energy harvesting devices such as photovoltaic (PV) devices and photo-electrochemical (PEC) solar water splitting devices. Extensive efforts have been exerted to improve the power conversion efficiencies (PCE) of such devices by utilizing novel nanostructures to revolutionize device structural designs. The thicknesses of light absorber and material consumption can be substantially reduced because of light trapping with nanostructures. Meanwhile, the utilization of nanostructures can also result in more effective carrier collection by shortening the photogenerated carrier collection path length. Nevertheless, performance optimization of nanostructured solar energy harvesting devices requires a rational design of various aspects of the nanostructures, such as their shape, aspect ratio, periodicity, etc. Without this, the utilization of nanostructures can lead to compromised device performance as the incorporation of these structures can result in defects and additional carrier recombination. The design guidelines of solar energy harvesting devices are summarized, including thin film non-uniformity on nanostructures, surface recombination, parasitic absorption, and the importance of uniform distribution of photo-generated carriers. A systematic view of the design concerns will assist better understanding of device physics and benefit the fabrication of high performance devices in the future.

  19. Energy harvesting from vibration with cross-linked polypropylene piezoelectrets

    Directory of Open Access Journals (Sweden)

    Xiaoqing Zhang

    2015-07-01

    Full Text Available Piezoelectret films are prepared by modification of the microstructure of polypropylene foam sheets cross-linked by electronic irradiation (IXPP, followed by proper corona charging. Young’s modulus, relative permittivity, and electromechanical coupling coefficient of the fabricated films, determined by dielectric resonance spectra, are about 0.7 MPa, 1.6, and 0.08, respectively. Dynamic piezoelectric d33 coefficients up to 650 pC/N at 200 Hz are achieved. The figure of merit (FOM, d33 ⋅ g33 for a more typical d33 value of 400 pC/N is about 11.2 GPa−1. Vibration-based energy harvesting with one-layer and two-layer stacks of these films is investigated at various frequencies and load resistances. At an optimum load resistance of 9 MΩ and a resonance frequency of 800 Hz, a maximum output power of 120 μW, referred to the acceleration g due to gravity, is obtained for an energy harvester consisting of a one-layer IXPP film with an area of 3.14 cm2 and a seismic mass of 33.7 g. The output power can be further improved by using two-layer stacks of IXPP films in electric series. IXPP energy harvesters could be used to energize low-power electronic devices, such as wireless sensors and LED lights.

  20. Energy harvesting from vibration with cross-linked polypropylene piezoelectrets

    Science.gov (United States)

    Zhang, Xiaoqing; Wu, Liming; Sessler, Gerhard M.

    2015-07-01

    Piezoelectret films are prepared by modification of the microstructure of polypropylene foam sheets cross-linked by electronic irradiation (IXPP), followed by proper corona charging. Young's modulus, relative permittivity, and electromechanical coupling coefficient of the fabricated films, determined by dielectric resonance spectra, are about 0.7 MPa, 1.6, and 0.08, respectively. Dynamic piezoelectric d33 coefficients up to 650 pC/N at 200 Hz are achieved. The figure of merit (FOM, d33 ṡ g33) for a more typical d33 value of 400 pC/N is about 11.2 GPa-1. Vibration-based energy harvesting with one-layer and two-layer stacks of these films is investigated at various frequencies and load resistances. At an optimum load resistance of 9 MΩ and a resonance frequency of 800 Hz, a maximum output power of 120 μW, referred to the acceleration g due to gravity, is obtained for an energy harvester consisting of a one-layer IXPP film with an area of 3.14 cm2 and a seismic mass of 33.7 g. The output power can be further improved by using two-layer stacks of IXPP films in electric series. IXPP energy harvesters could be used to energize low-power electronic devices, such as wireless sensors and LED lights.

  1. Energy harvesting from vibration with cross-linked polypropylene piezoelectrets

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xiaoqing [Shanghai Key Laboratory of Special Artificial Microstructure Materials and Technology & School of Physics Science and Engineering, Tongji University, Shanghai 200092 (China); Institute for Telecommunications Technology, Merckstrasse 25, 64283 Darmstadt (Germany); Wu, Liming [Shanghai Key Laboratory of Special Artificial Microstructure Materials and Technology & School of Physics Science and Engineering, Tongji University, Shanghai 200092 (China); Sessler, Gerhard M., E-mail: g.sessler@nt.tu-darmstadt.de [Institute for Telecommunications Technology, Merckstrasse 25, 64283 Darmstadt (Germany)

    2015-07-15

    Piezoelectret films are prepared by modification of the microstructure of polypropylene foam sheets cross-linked by electronic irradiation (IXPP), followed by proper corona charging. Young’s modulus, relative permittivity, and electromechanical coupling coefficient of the fabricated films, determined by dielectric resonance spectra, are about 0.7 MPa, 1.6, and 0.08, respectively. Dynamic piezoelectric d{sub 33} coefficients up to 650 pC/N at 200 Hz are achieved. The figure of merit (FOM, d{sub 33} ⋅ g{sub 33}) for a more typical d{sub 33} value of 400 pC/N is about 11.2 GPa{sup −1}. Vibration-based energy harvesting with one-layer and two-layer stacks of these films is investigated at various frequencies and load resistances. At an optimum load resistance of 9 MΩ and a resonance frequency of 800 Hz, a maximum output power of 120 μW, referred to the acceleration g due to gravity, is obtained for an energy harvester consisting of a one-layer IXPP film with an area of 3.14 cm{sup 2} and a seismic mass of 33.7 g. The output power can be further improved by using two-layer stacks of IXPP films in electric series. IXPP energy harvesters could be used to energize low-power electronic devices, such as wireless sensors and LED lights.

  2. Toward efficient aeroelastic energy harvesting through limit cycle shaping

    Science.gov (United States)

    Kirschmeier, Benjamin; Bryant, Matthew

    2016-04-01

    Increasing demand to harvest energy from renewable resources has caused significant research interest in unsteady aerodynamic and hydrodynamic phenomena. Apart from the traditional horizontal axis wind turbines, there has been significant growth in the study of bio-inspired oscillating wings for energy harvesting. These systems are being built to harvest electricity for wireless devices, as well as for large scale mega-watt power generation. Such systems can be driven by aeroelastic flutter phenomena which, beyond a critical wind speed, will cause the system to enter into limitcycle oscillations. When the airfoil enters large amplitude, high frequency motion, leading and trailing edge vortices form and, when properly synchronized with the airfoil kinematics, enhance the energy extraction efficiency of the device. A reduced order dynamic stall model is employed on a nonlinear aeroelastic structural model to investigate whether the parameters of a fully passive aeroelastic device can be tuned to produce limit cycle oscillations at desired kinematics. This process is done through an optimization technique to find the necessary structural parameters to achieve desired structural forces and moments corresponding to a target limit cycle. Structural nonlinearities are explored to determine the essential nonlinearities such that the system's limit cycle closely matches the desired kinematic trajectory. The results from this process demonstrate that it is possible to tune system parameters such that a desired limit cycle trajectory can be achieved. The simulations also demonstrate that the high efficiencies predicted by previous computational aerodynamics studies can be achieved in fully passive aeroelastic devices.

  3. Piezoelectric compliant mechanism energy harvesters under large base excitations

    Science.gov (United States)

    Ma, Xiaokun; Trolier-McKinstry, Susan; Rahn, Christopher D.

    2016-09-01

    A piezoelectric compliant mechanism (PCM) energy harvester is designed, modeled, and analyzed that consists of a polyvinylidene diflouoride, PVDF unimorph clamped at its base and attached to a compliant mechanism at its tip. The compliant hinge stiffness is carefully tuned to approach a low frequency first mode with an efficient (nearly quadratic) shape that provides a uniform strain distribution. A nonlinear model of the PCM energy harvester under large base excitation is derived to determine the maximum power that can be generated by the device. Experiments with a fabricated PCM energy harvester prototype show that the compliant mechanism introduces a stiffening effect and a much wider bandwidth than a benchmark proof mass cantilever design. The PCM bridge structure self-limits the displacement and maximum strain at large excitations compared with the proof mass cantilever, improving the device robustness. The PCM outperforms the cantilever in both average power and power-strain sensitivity at high accelerations due to the PCM axial stretching effect and its more uniform strain distribution.

  4. Corrugated Textile based Triboelectric Generator for Wearable Energy Harvesting

    Science.gov (United States)

    Choi, A Young; Lee, Chang Jun; Park, Jiwon; Kim, Dogyun; Kim, Youn Tae

    2017-01-01

    Triboelectric energy harvesting has been applied to various fields, from large-scale power generation to small electronics. Triboelectric energy is generated when certain materials come into frictional contact, e.g., static electricity from rubbing a shoe on a carpet. In particular, textile-based triboelectric energy-harvesting technologies are one of the most promising approaches because they are not only flexible, light, and comfortable but also wearable. Most previous textile-based triboelectric generators (TEGs) generate energy by vertically pressing and rubbing something. However, we propose a corrugated textile-based triboelectric generator (CT-TEG) that can generate energy by stretching. Moreover, the CT-TEG is sewn into a corrugated structure that contains an effective air gap without additional spacers. The resulting CT-TEG can generate considerable energy from various deformations, not only by pressing and rubbing but also by stretching. The maximum output performances of the CT-TEG can reach up to 28.13 V and 2.71 μA with stretching and releasing motions. Additionally, we demonstrate the generation of sufficient energy from various activities of a human body to power about 54 LEDs. These results demonstrate the potential application of CT-TEGs for self-powered systems.

  5. Buckled graphene for efficient energy harvest, storage and conversion

    Science.gov (United States)

    Jiang, Jin-Wu

    2016-10-01

    Buckling is one of the most common phenomena in atom-thick layered structures like graphene. While the buckling phenomenon usually causes disaster for most nanodevices, we illustrate one positive application of buckled graphene for energy harvest, storage and conversion. More specifically, we perform molecular dynamical simulations to show that buckled graphene can be used to collect wasted mechanical energy and store the energy in the form of internal knotting potential. Through strain engineering, the knotting potential can be converted into useful kinetic (thermal) energy that is highly concentrated at the free edges of buckled graphene. The present study demonstrates potential applications of buckled graphene for converting dispersed wasted mechanical energy into concentrated useful kinetic (thermal) energy.

  6. Mechanisms of Light Energy Harvesting in Dendrimers and Hyperbranched Polymers

    Directory of Open Access Journals (Sweden)

    David L. Andrews

    2011-12-01

    Full Text Available Since their earliest synthesis, much interest has arisen in the use of dendritic and structurally allied forms of polymer for light energy harvesting, especially as organic adjuncts for solar energy devices. With the facility to accommodate a proliferation of antenna chromophores, such materials can capture and channel light energy with a high degree of efficiency, each polymer unit potentially delivering the energy of one photon—or more, when optical nonlinearity is involved. To ensure the highest efficiency of operation, it is essential to understand the processes responsible for photon capture and channelling of the resulting electronic excitation. Highlighting the latest theoretical advances, this paper reviews the principal mechanisms, which prove to involve a complex interplay of structural, spectroscopic and electrodynamic properties. Designing materials with the capacity to capture and control light energy facilitates applications that now extend from solar energy to medical photonics.

  7. Buckled graphene for efficient energy harvest, storage and conversion.

    Science.gov (United States)

    Jiang, Jin-Wu

    2016-10-01

    Buckling is one of the most common phenomena in atom-thick layered structures like graphene. While the buckling phenomenon usually causes disaster for most nanodevices, we illustrate one positive application of buckled graphene for energy harvest, storage and conversion. More specifically, we perform molecular dynamical simulations to show that buckled graphene can be used to collect wasted mechanical energy and store the energy in the form of internal knotting potential. Through strain engineering, the knotting potential can be converted into useful kinetic (thermal) energy that is highly concentrated at the free edges of buckled graphene. The present study demonstrates potential applications of buckled graphene for converting dispersed wasted mechanical energy into concentrated useful kinetic (thermal) energy.

  8. A broadband quad-stable energy harvester and its advantages over bi-stable harvester: Simulation and experiment verification

    Science.gov (United States)

    Zhou, Zhiyong; Qin, Weiyang; Zhu, Pei

    2017-02-01

    This paper presents a novel quad-stable energy harvester (QEH) to harvest vibration energy. The QEH is composed of a piezoelectric bimorph cantilever beam with a tip magnet and three external fixed magnets. The potential energy of the QEH is derived, which has four potential wells and three low barriers. This implies that the QEH needs relatively lower excitation energy to cross the barriers than the bi-stable energy harvester (BEH). Simulations are carried out for the BEH and QEH at different levels of excitations. Results show that the QEH owns a smaller threshold and a wider range of frequencies for occurrence of snap-through than the BEH. Thus the QEH can give out a large output voltage. Corresponding experiments were performed for validation. The experimental results are in agreement with the simulations, which means that the QEH can improve the harvesting efficiency considerably.

  9. Low power interface IC's for electrostatic energy harvesting applications

    Science.gov (United States)

    Kempitiya, Asantha

    The application of wireless distributed micro-sensor systems ranges from equipment diagnostic and control to real time structural and biomedical monitoring. A major obstacle in developing autonomous micro-sensor networks is the need for local electric power supply, since using a battery is often not a viable solution. This void has sparked significant interest in micro-scale power generators based on electrostatic, piezoelectric and electromagnetic energy conversion that can scavenge ambient energy from the environment. In comparison to existing energy harvesting techniques, electrostatic-based power generation is attractive as it can be integrated using mainstream silicon technologies while providing higher power densities through miniaturization. However the power output of reported electrostatic micro-generators to date does not meet the communication and computation requirements of wireless sensor nodes. The objective of this thesis is to investigate novel CMOS-based energy harvesting circuit (EHC) architectures to increase the level of harvested mechanical energy in electrostatic converters. The electronic circuits that facilitate mechanical to electrical energy conversion employing variable capacitors can either have synchronous or asynchronous architectures. The later does not require synchronization of electrical events with mechanical motion, which eliminates difficulties in gate clocking and the power consumption associated with complex control circuitry. However, the implementation of the EHC with the converter can be detrimental to system performance when done without concurrent optimization of both elements, an aspect mainly overlooked in the literature. System level analysis is performed to show that there is an optimum value for either the storage capacitor or cycle number for maximum scavenging of ambient energy. The analysis also shows that maximum power is extracted when the system approaches synchronous operation. However, there is a region of

  10. Magneto-Thermo-Triboelectric Generator (MTTG) for thermal energy harvesting

    Science.gov (United States)

    Jang, Kwang Yeop; Lee, James; Lee, Dong-Gun

    2016-04-01

    We present a novel thermal energy harvesting system using triboelectric effect. Recently, there has been intensive research efforts on energy harvesting using triboelectric effect, which can produce surprising amount of electric power (when compared to piezoelectric materials) by rubbing or touching (i.e, electric charge by contact and separation) two different materials together. Numerous studies have shown the possibility as an attractive alternative with good transparency, flexibility and low cost abilities for its use in wearable device and smart phone applications markets. However, its application has been limited to only vibration source, which can produce sustained oscillation with maintaining contact and separation states repeatedly for triboelectric effect. Thus, there has been no attempt toward thermal energy source. The proposed approach can convert thermal energy into electricity by pairing triboelectric effect and active ferromagnetic materials The objective of the research is to develop a new manufacturing process of design, fabrication, and testing of a Magneto-Thermo-Triboelectric Generator (MTTG). The results obtained from the approach show that MTTG devices have a feasible power energy conversion capability from thermal energy sources. The tunable design of the device is such that it has efficient thermal capture over a wide range of operation temperature in waste heat.

  11. Graphene-Based Integrated Photovoltaic Energy Harvesting/Storage Device.

    Science.gov (United States)

    Chien, Chih-Tao; Hiralal, Pritesh; Wang, Di-Yan; Huang, I-Sheng; Chen, Chia-Chun; Chen, Chun-Wei; Amaratunga, Gehan A J

    2015-06-24

    Energy scavenging has become a fundamental part of ubiquitous sensor networks. Of all the scavenging technologies, solar has the highest power density available. However, the energy source is erratic. Integrating energy conversion and storage devices is a viable route to obtain self-powered electronic systems which have long-term maintenance-free operation. In this work, we demonstrate an integrated-power-sheet, consisting of a string of series connected organic photovoltaic cells (OPCs) and graphene supercapacitors on a single substrate, using graphene as a common platform. This results in lighter and more flexible power packs. Graphene is used in different forms and qualities for different functions. Chemical vapor deposition grown high quality graphene is used as a transparent conductor, while solution exfoliated graphene pastes are used as supercapacitor electrodes. Solution-based coating techniques are used to deposit the separate components onto a single substrate, making the process compatible with roll-to-roll manufacture. Eight series connected OPCs based on poly(3-hexylthiophene)(P3HT):phenyl-C61-butyric acid methyl ester (PC60 BM) bulk-heterojunction cells with aluminum electrodes, resulting in a ≈5 V open-circuit voltage, provide the energy harvesting capability. Supercapacitors based on graphene ink with ≈2.5 mF cm(-2) capacitance provide the energy storage capability. The integrated-power-sheet with photovoltaic (PV) energy harvesting and storage functions had a mass of 0.35 g plus the substrate.

  12. Piezoelectric ZnO nanostructure for energy harvesting

    CERN Document Server

    Leprince-Wang, Yamin

    2015-01-01

    Over the past decade, ZnO as an important II-VI semiconductor has attracted much attention within the scientific community over the world owing to its numerous unique and prosperous properties. This material, considered as a "future material", especially in nanostructural format, has aroused many interesting research works due to its large range of applications in electronics, photonics, acoustics, energy and sensing. The bio-compatibility, piezoelectricity & low cost fabrication make ZnO nanostructure a very promising material for energy harvesting.

  13. Fabrication and characterization of a low frequency electromagnetic energy harvester

    Institute of Scientific and Technical Information of China (English)

    Abu Riduan Md.Foisal; Gwiy-Sang Chung

    2012-01-01

    This paper presents the fabrication and characterization of an AA size electromagnetic energy transducer based on vibration.A magnetic spring technique is used to scavenge energy from low frequency external vibration.The output of the harvester is maximized by optimizing the mass of moving and fixed magnets,coil width,coil position and load resistance through a comprehensive experimental analysis.The prototype can generate an open circuit voltage of 3.961 V and 1.18 mW average power at a load resistance of 97 Ω with 9 Hz resonance frequency and 0.5 mm displacement.

  14. A Monolithic Oxide-Based Transversal Thermoelectric Energy Harvester

    Science.gov (United States)

    Teichert, S.; Bochmann, A.; Reimann, T.; Schulz, T.; Dreßler, C.; Udich, S.; Töpfer, J.

    2016-03-01

    We report the fabrication and properties of a monolithic transversal thermoelectric energy harvester based on the combination of a thermoelectric oxide and a metal. The fabrication of the device is done with a ceramic multilayer technology using printing and co-firing processes. Five transversal devices were combined to a meander-like thermoelectric generator. Electrical measurements and finite element calculations were performed to characterize the resulting thermoelectric generator. A maximum experimental electrical power output of 30.2 mW at a temperature difference of {Δ }T = 208 K was found. The prepared monolithic thermoelectric generator provides at {Δ }T = 35 K sufficient energy to drive a simple electronic sensor application.

  15. Adaptive Media Access Control for Energy Harvesting - Wireless Sensor Networks

    DEFF Research Database (Denmark)

    Fafoutis, Xenofon; Dragoni, Nicola

    2012-01-01

    ODMAC (On-Demand Media Access Control) is a recently proposed MAC protocol designed to support individual duty cycles for Energy Harvesting — Wireless Sensor Networks (EH-WSNs). Individual duty cycles are vital for EH-WSNs, because they allow nodes to adapt their energy consumption to the ever......-changing environmental energy sources. In this paper, we present an improved and extended version of ODMAC and we analyze it by means of an analytical model that can approximate several performance metrics in an arbitrary network topology. The simulations and the analytical experiments show ODMAC's ability to satisfy...... three key properties of EH-WSNs: adaptability of energy consumption, distributed energy-aware load balancing and support for different application-specific requirements....

  16. Optimal Packet Scheduling on an Energy Harvesting Fading Channel

    CERN Document Server

    Ozcelik, F Mehmet; Uysal-Biyikoglu, Elif

    2012-01-01

    An offline transmission completion time minimization problem for an energy harvesting transmitter is considered. Specifically, optimal power and rate allocation for data packets arriving at arbitrary but known instances is studied. Communication takes place under a fading channel and transmitter is restricted with a limited energy storage capability. An optimal policy takes into account the channel state as well as the state of energy and data buffers. Moreover, the solution needs to strike a tradeoff between energy efficiency and delay. By exhibiting an equivalent convex problem, the unique optimal scheduling solution is obtained through an iterative convex optimization technique, sequential unconstrained minimization. The optimal solution under finite and infinite energy storage is examined on problem instances.

  17. Thermoelectric energy harvesting from small ambient temperature transients

    Energy Technology Data Exchange (ETDEWEB)

    Moser, Andre

    2012-07-01

    Wireless sensor networks (WSNs) represent a key technology, used, for instance, in structural health monitoring, building automation systems, or traffic surveillance. Supplying power to a network of spatially distributed sensor nodes, especially at remote locations, is a large challenge: power grids are reliable but costly to install, whereas batteries provide a high flexibility in the installation but have a limited lifetime. This dilemma can be overcome by micro energy harvesting which offers both: reliability and flexibility. Micro energy harvesters are able to convert low grade ambient energy into useful electrical energy and thus provide power for wireless sensor networks or other electronic devices - in-situ, off-grid, and with an almost unlimited lifetime. Thermal energy is an omnipresent source of ambient energy: The day-night-cycle of the sun causes a temperature variation in the ambient air as well as arbitrary solids (soil, building walls, etc.). Unlike the air, solids have a large thermal inertia which dampens the temperature variation. This physical process leads to a temperature difference {Delta}T = T{sub air} - T{sub solid} between air and solid that can be converted directly into electrical energy by a thermoelectric generator (TEG). Thermal and electrical interfaces are necessary to connect the TEG to the thermal energy source (T{sub air}, T{sub solid}) and the electrical load (WSN). Reliable operation of the WSN may only be ensured if the harvester provides sufficient electrical energy, i.e. operates at its maximum power point. The goal of this thesis is to study, design, and test thermoelectric harvesters generating electrical energy from small ambient temperature transients in order to self-sufficiently power a WSN. Current research into thermoelectric energy harvesting, especially analytical modeling and application in the field are treated insufficiently. Therefore, a time-dependent analytical model of the harvester's output power is set

  18. Graphene rectenna for efficient energy harvesting at terahertz frequencies

    Science.gov (United States)

    Dragoman, Mircea; Aldrigo, Martino

    2016-09-01

    In this paper, we propose a graphene rectenna that encompasses two distinct functions in a single device, namely, antenna and rectifier, which till now were two separate components. In this way, the rectenna realizes an efficient energy harvesting technique due to the absence of impedance mismatch between antenna and diode. In particular, we have obtained a maximum conversion efficiency of 58.43% at 897 GHz for the graphene rectenna on n-doped GaAs, which is a very good value, close to the performance of an RF harvesting system. A comparison with a classical metallic antenna with an HfO2-based metal-insulator-metal diode is also provided.

  19. Electret-based cantilever energy harvester: design and optimization

    CERN Document Server

    Boisseau, S; Sylvestre, A

    2011-01-01

    We report in this paper the design, the optimization and the fabrication of an electret-based cantilever energy harvester. We develop the mechanical and the electrostatic equations of such a device and its implementation using Finite Elements (FEM) and Matlab in order to get an accurate model. This model is then used in an optimization process. A macroscopic prototype (3.2cm^{2}) was built with a silicon cantilever and a Teflon\\textregistered electret. Thanks to this prototype, we manage to harvest 17\\muW with ambient-type vibrations of 0.2g on a load of 210M{\\Omega}. The experimental results are consistent with simulation results.

  20. Energy harvesting performance of piezoelectric ceramic and polymer nanowires

    Science.gov (United States)

    Crossley, Sam; Kar-Narayan, Sohini

    2015-08-01

    Energy harvesting from ubiquitous ambient vibrations is attractive for autonomous small-power applications and thus considerable research is focused on piezoelectric materials as they permit direct inter-conversion of mechanical and electrical energy. Nanogenerators (NGs) based on piezoelectric nanowires are particularly attractive due to their sensitivity to small-scale vibrations and may possess superior mechanical-to-electrical conversion efficiency when compared to bulk or thin-film devices of the same material. However, candidate piezoelectric nanowires have hitherto been predominantly analyzed in terms of NG output (i.e. output voltage, output current and output power density). Surprisingly, the corresponding dynamical properties of the NG, including details of how the nanowires are mechanically driven and its impact on performance, have been largely neglected. Here we investigate all realizable NG driving contexts separately involving inertial displacement, applied stress T and applied strain S, highlighting the effect of driving mechanism and frequency on NG performance in each case. We argue that, in the majority of cases, the intrinsic high resonance frequencies of piezoelectric nanowires (∼tens of MHz) present no barrier to high levels of NG performance even at frequencies far below resonance (materials properties, for comparing piezoelectric NG performance under strain-driven and stress-driven conditions respectively. These figures of merit permit, for the first time, a general comparison of piezoelectric nanowires for NG applications that takes into account the nature of the mechanical excitation. We thus investigate the energy harvesting performance of prototypical piezoelectric ceramic and polymer nanowires. We find that even though ceramic and polymer nanowires have been found, in certain cases, to have similar energy conversion efficiencies, ceramics are more promising in strain-driven NGs while polymers are more promising for stress-driven NGs

  1. Toward Low-Frequency Mechanical Energy Harvesting Using Energy-Dense Piezoelectrochemical Materials.

    Science.gov (United States)

    Cannarella, John; Arnold, Craig B

    2015-12-02

    The piezoelectrochemical coupling between mechanical stress and electrochemical potential is explored in the context of mechanical energy harvesting and shown to have promise in developing high-energy-density harvesters for low-frequency applications (e.g., human locomotion). This novel concept is demonstrated experimentally by cyclically compressing an off-the-shelf lithium-ion battery and measuring the generated electric power output.

  2. Barium Titanate Film Interfaces for Hybrid Composite Energy Harvesters.

    Science.gov (United States)

    Bowland, Christopher C; Malakooti, Mohammad H; Sodano, Henry A

    2017-02-01

    Energy harvesting utilizing piezoelectric materials has become an attractive approach for converting mechanical energy into electrical power for low-power electronics. Structural composites are ideally suited for energy scavenging due to the large amount of mechanical energy they are subjected to. Here, a multifunctional composite with embedded sensing and energy harvesting is developed by integrating an active interface into carbon fiber reinforced polymer composites. By modifying the composite matrix, both rigid and flexible multifunctional composites are fabricated. Through electromechanical testing of a cantilever beam of the rigid composite, it reveals a power density of 217 pW/cc from only 1 g root-mean-square acceleration when excited at its resonant frequency of 47 Hz. Electromechanical sensor testing of the flexible multifunctional composite reveals an average voltage generation of 23.5 mV/g at its resonant frequency of 96 Hz. This research introduces a route for integrating nonstructural functionality into structural fiber composites by utilizing BaTiO3 coated woven carbon fiber fabrics with power scavenging and passive sensing capabilities.

  3. The potential for harvesting energy from the movement of trees.

    Science.gov (United States)

    McGarry, Scott; Knight, Chris

    2011-01-01

    Over the last decade, wireless devices have decreased in size and power requirements. These devices generally use batteries as a power source but can employ additional means of power, such as solar, thermal or wind energy. However, sensor networks are often deployed in conditions of minimal lighting and thermal gradient such as densely wooded environments, where even normal wind energy harvesting is limited. In these cases a possible source of energy is from the motion of the trees themselves. We investigated the amount of energy and power available from the motion of a tree in a sheltered position, during Beaufort 4 winds. We measured the work performed by the tree to lift a mass, we measured horizontal acceleration of free movement, and we determined the angular deflection of the movement of the tree trunk, to determine the energy and power available to various types of harvesting devices. We found that the amount of power available from the tree, as demonstrated by lifting a mass, compares favourably with the power required to run a wireless sensor node.

  4. Hybrid energy harvesting systems, using piezoelectric elements and dielectric polymers

    Science.gov (United States)

    Cornogolub, Alexandru; Cottinet, Pierre-Jean; Petit, Lionel

    2016-09-01

    Interest in energy harvesting applications has increased a lot during recent years. This is especially true for systems using electroactive materials like dielectric polymers or piezoelectric materials. Unfortunately, these materials despite multiple advantages, present some important drawbacks. For example, many dielectric polymers demonstrated high energy densities; they are cheap, easy to process and can be easily integrated in many different structures. But at the same time, dielectric polymer generators require an external energy supply which could greatly compromise their autonomy. Piezoelectric systems, on the other hand, are completely autonomous and can be easily miniaturized. However, most common piezoelectric materials present a high rigidity and are brittle by nature and therefore their integration could be difficult. This paper investigates the possibility of using hybrid systems combining piezoelectric elements and dielectric polymers for mechanical energy harvesting applications and it is focused mainly on the problem of electrical energy transfer. Our objective is to show that such systems can be interesting and that it is possible to benefit from the advantages of both materials. For this, different configurations were considered and the problem of their optimization was addressed. The experimental work enabled us to prove the concept and identify the main practical limitations.

  5. The Potential for Harvesting Energy from the Movement of Trees

    Directory of Open Access Journals (Sweden)

    Chris Knight

    2011-09-01

    Full Text Available Over the last decade, wireless devices have decreased in size and power requirements. These devices generally use batteries as a power source but can employ additional means of power, such as solar, thermal or wind energy. However, sensor networks are often deployed in conditions of minimal lighting and thermal gradient such as densely wooded environments, where even normal wind energy harvesting is limited. In these cases a possible source of energy is from the motion of the trees themselves. We investigated the amount of energy and power available from the motion of a tree in a sheltered position, during Beaufort 4 winds. We measured the work performed by the tree to lift a mass, we measured horizontal acceleration of free movement, and we determined the angular deflection of the movement of the tree trunk, to determine the energy and power available to various types of harvesting devices. We found that the amount of power available from the tree, as demonstrated by lifting a mass, compares favourably with the power required to run a wireless sensor node.

  6. Design & Implementation of a Mobile Phone Charging System Based on Solar Energy Harvesting

    Directory of Open Access Journals (Sweden)

    Qutaiba I. Ali

    2011-06-01

    Full Text Available The ability to harvest energy from the environment represents an important technology area that promises to eliminate wires and battery maintenance for many important applications and permits deploying self powered devices. This paper suggests the use of a solar energy harvester to charge mobile phone devices. In the beginning, a comprehensive overview to the energy harvesting concept and technologies is presented. Then the design procedure of our energy harvester was detailed. Our prototype solar energy harvester proves its efficiency to charge the aimed batteries under sunlight or an indoor artificial light.

  7. Global stabilization of high-energy resonance for a nonlinear wideband electromagnetic vibration energy harvester

    Science.gov (United States)

    Masuda, Arata; Sato, Takeru

    2016-04-01

    This paper presents an experimental verification of a wideband nonlinear vibration energy harvester which has a globally stabilized high-energy resonating response. For the conventional linear vibration energy harvester, the maximum performance of the power generation and its bandwidth are in a relation of trade-off. The resonance frequency band can be expanded by introducing a Duffing-type nonlinear resonator in order to enable the harvester to generate larger electric power in a wider frequency range. However, since such nonlinear resonators often have multiple stable steady-state solutions in the resonance band, it is difficult for the nonlinear harvester to maintain the high performance of the power generation constantly. The principle of self-excitation and entrainment has been utilized to provide the global stability to the highest-energy solution by destabilizing other unexpected lower-energy solutions by introducing a switching circuit of the load resistance between positive and the negative values depending on the response amplitude of the oscillator. In this study, an experimental verification of this concept are carried out. An experimental prototype harvester is designed and fabricated and the performance of the proposed harvester is experimentally verified. It has been shown that the numerical and experimental results agreed very well, and the highest-energy solutions above the threshold value were successfully stabilized globally.

  8. Energy harvesting performance of piezoelectric ceramic and polymer nanowires.

    Science.gov (United States)

    Crossley, Sam; Kar-Narayan, Sohini

    2015-08-28

    Energy harvesting from ubiquitous ambient vibrations is attractive for autonomous small-power applications and thus considerable research is focused on piezoelectric materials as they permit direct inter-conversion of mechanical and electrical energy. Nanogenerators (NGs) based on piezoelectric nanowires are particularly attractive due to their sensitivity to small-scale vibrations and may possess superior mechanical-to-electrical conversion efficiency when compared to bulk or thin-film devices of the same material. However, candidate piezoelectric nanowires have hitherto been predominantly analyzed in terms of NG output (i.e. output voltage, output current and output power density). Surprisingly, the corresponding dynamical properties of the NG, including details of how the nanowires are mechanically driven and its impact on performance, have been largely neglected. Here we investigate all realizable NG driving contexts separately involving inertial displacement, applied stress T and applied strain S, highlighting the effect of driving mechanism and frequency on NG performance in each case. We argue that, in the majority of cases, the intrinsic high resonance frequencies of piezoelectric nanowires (∼tens of MHz) present no barrier to high levels of NG performance even at frequencies far below resonance (energy harvesting (VEH) coefficients ηS and ηT, based on intrinsic materials properties, for comparing piezoelectric NG performance under strain-driven and stress-driven conditions respectively. These figures of merit permit, for the first time, a general comparison of piezoelectric nanowires for NG applications that takes into account the nature of the mechanical excitation. We thus investigate the energy harvesting performance of prototypical piezoelectric ceramic and polymer nanowires. We find that even though ceramic and polymer nanowires have been found, in certain cases, to have similar energy conversion efficiencies, ceramics are more promising in strain

  9. Efficiency Enhancement of a Cantilever-Based Vibration Energy Harvester

    Directory of Open Access Journals (Sweden)

    Ali E. Kubba

    2013-12-01

    Full Text Available Extracting energy from ambient vibration to power wireless sensor nodes has been an attractive area of research, particularly in the automotive monitoring field. This article reports the design, analysis and testing of a vibration energy harvesting device based on a miniature asymmetric air-spaced cantilever. The developed design offers high power density, and delivers electric power that is sufficient to support most wireless sensor nodes for structural health monitoring (SHM applications. The optimized design underwent three evolutionary steps, starting from a simple cantilever design, going through an air-spaced cantilever, and ending up with an optimized air-spaced geometry with boosted power density level. Finite Element Analysis (FEA was used as an initial tool to compare the three geometries’ stiffness (K, output open-circuit voltage (Vave, and average normal strain in the piezoelectric transducer (εave that directly affect its output voltage. Experimental tests were also carried out in order to examine the energy harvesting level in each of the three designs. The experimental results show how to boost the power output level in a thin air-spaced cantilever beam for energy within the same space envelope. The developed thin air-spaced cantilever (8.37 cm3, has a maximum power output of 2.05 mW (H = 29.29 μJ/cycle.

  10. Consideration of impedance matching techniques for efficient piezoelectric energy harvesting.

    Science.gov (United States)

    Kim, Hyeoungwoo; Priya, Shashank; Stephanou, Harry; Uchino, Kenji

    2007-09-01

    This study investigates multiple levels of impedance-matching methods for piezoelectric energy harvesting in order to enhance the conversion of mechanical to electrical energy. First, the transduction rate was improved by using a high piezoelectric voltage constant (g) ceramic material having a magnitude of g33 = 40 x 10(-3) V m/N. Second, a transducer structure, cymbal, was optimized and fabricated to match the mechanical impedance of vibration source to that of the piezoelectric transducer. The cymbal transducer was found to exhibit approximately 40 times higher effective strain coefficient than the piezoelectric ceramics. Third, the electrical impedance matching for the energy harvesting circuit was considered to allow the transfer of generated power to a storage media. It was found that, by using the 10-layer ceramics instead of the single layer, the output current can be increased by 10 times, and the output load can be reduced by 40 times. Furthermore, by using the multilayer ceramics the output power was found to increase by 100%. A direct current (DC)-DC buck converter was fabricated to transfer the accumulated electrical energy in a capacitor to a lower output load. The converter was optimized such that it required less than 5 mW for operation.

  11. Bio-kinetic energy harvesting using electroactive polymers

    Science.gov (United States)

    Slade, Jeremiah R.; Bowman, Jeremy; Kornbluh, Roy

    2012-06-01

    In hybrid vehicles, electric motors are used on each wheel to not only propel the car but also to decelerate the car by acting as generators. In the case of the human body, muscles spend about half of their time acting as a brake, absorbing energy, or doing what is known as negative work. Using dielectric elastomers it is possible to use the "braking" phases of walking to generate power without restricting or fatiguing the Warfighter. Infoscitex and SRI have developed and demonstrated methods for using electroactive polymers (EAPs) to tap into the negative work generated at the knee during the deceleration phase of the human gait cycle and convert it into electrical power that can be used to support wearable information systems, including display and communication technologies. The specific class of EAP that has been selected for these applications is termed dielectric elastomers. Because dielectric elastomers dissipate very little mechanical energy into heat, greater amounts of energy can be converted into electricity than by any other method. The long term vision of this concept is to have EAP energy harvesting cells located in components of the Warfighter ensemble, such as the boot uppers, knee pads and eventually even the clothing itself. By properly locating EAPs at these sites it will be possible to not only harvest power from the negative work phase but to actually reduce the amount of work done by the Warfighter's muscles during this phase, thereby reducing fatigue and minimizing the forces transmitted to the joints.

  12. Thermal Energy Harvesting Using Pyroelectric and Piezoelectric Effect

    Science.gov (United States)

    Kang, Miwon; Yeatman, Eric M.

    2016-11-01

    This paper presents a prototype of a thermal energy harvesting mechanism using both pyroelectric and piezoelectric effect. Thermal energy is one of abundant energy sources from various processes. Waste heat from a chip on a circuit board of the electronic device involves temperature differences from a few degrees C to over 100 °C. Therefore, 95 °C of a heat reservoir was used in this study. A repetitive time-dependant temperature variation is applied by a linear sliding table. The influence of heat conditions was investigated, by changing velocity and frequency of this linear sliding table. This energy harvesting mechanism employs Lead Zirconate Titanate (PZT-5H), a bimetal beam and two neodymium magnets. The pyroelectric effect is caused by a time-dependent temperature variation, and the piezoelectric effect is caused by stress from deformation of the bimetal. A maximum power output 0.54 μW is obtained at an optimal condition when the load resistance is 610 kΩ.

  13. An estimate of spherical impactor energy transfer for mechanical frequency up-conversion energy harvester

    Science.gov (United States)

    Corr, L. R.; Ma, D. T.

    2016-08-01

    Vibration energy harvesters, which use the impact mechanical frequency up-conversion technique, utilize an impactor, which gains kinetic energy from low frequency ambient environmental vibrations, to excite high frequency systems that efficiently convert mechanical energy to electrical energy. To take full advantage of the impact mechanical frequency up-conversion technique, it is prudent to understand the energy transfer from the low frequency excitations, to the impactor, and finally to the high frequency systems. In this work, the energy transfer from a spherical impactor to a multi degree of freedom spring / mass system, due to Hertzian impact, is investigated to gain insight on how best to design impact mechanical frequency up-conversion energy harvesters. Through this academic work, it is shown that the properties of the contact (or impact) area, i.e., radius of curvature and material properties, only play a minor role in energy transfer and that the equivalent mass of the target system (i.e., the spring / mass system) dictates the total amount of energy transferred during the impact. The novel approach of utilizing the well-known Hertzian impact methodology to gain an understanding of impact mechanical frequency up-conversion energy harvesters has made it clear that the impactor and the high frequency energy generating systems must be designed together as one system to ensure maximum energy transfer, leading to efficient ambient vibration energy harvesters.

  14. Outage Probability Minimization for Energy Harvesting Cognitive Radio Sensor Networks.

    Science.gov (United States)

    Zhang, Fan; Jing, Tao; Huo, Yan; Jiang, Kaiwei

    2017-01-24

    The incorporation of cognitive radio (CR) capability in wireless sensor networks yields a promising network paradigm known as CR sensor networks (CRSNs), which is able to provide spectrum efficient data communication. However, due to the high energy consumption results from spectrum sensing, as well as subsequent data transmission, the energy supply for the conventional sensor nodes powered by batteries is regarded as a severe bottleneck for sustainable operation. The energy harvesting technique, which gathers energy from the ambient environment, is regarded as a promising solution to perpetually power-up energy-limited devices with a continual source of energy. Therefore, applying the energy harvesting (EH) technique in CRSNs is able to facilitate the self-sustainability of the energy-limited sensors. The primary concern of this study is to design sensing-transmission policies to minimize the long-term outage probability of EH-powered CR sensor nodes. We formulate this problem as an infinite-horizon discounted Markov decision process and propose an ϵ-optimal sensing-transmission (ST) policy through using the value iteration algorithm. ϵ is the error bound between the ST policy and the optimal policy, which can be pre-defined according to the actual need. Moreover, for a special case that the signal-to-noise (SNR) power ratio is sufficiently high, we present an efficient transmission (ET) policy and prove that the ET policy achieves the same performance with the ST policy. Finally, extensive simulations are conducted to evaluate the performance of the proposed policies and the impaction of various network parameters.

  15. Outage Probability Minimization for Energy Harvesting Cognitive Radio Sensor Networks

    Directory of Open Access Journals (Sweden)

    Fan Zhang

    2017-01-01

    Full Text Available The incorporation of cognitive radio (CR capability in wireless sensor networks yields a promising network paradigm known as CR sensor networks (CRSNs, which is able to provide spectrum efficient data communication. However, due to the high energy consumption results from spectrum sensing, as well as subsequent data transmission, the energy supply for the conventional sensor nodes powered by batteries is regarded as a severe bottleneck for sustainable operation. The energy harvesting technique, which gathers energy from the ambient environment, is regarded as a promising solution to perpetually power-up energy-limited devices with a continual source of energy. Therefore, applying the energy harvesting (EH technique in CRSNs is able to facilitate the self-sustainability of the energy-limited sensors. The primary concern of this study is to design sensing-transmission policies to minimize the long-term outage probability of EH-powered CR sensor nodes. We formulate this problem as an infinite-horizon discounted Markov decision process and propose an ϵ-optimal sensing-transmission (ST policy through using the value iteration algorithm. ϵ is the error bound between the ST policy and the optimal policy, which can be pre-defined according to the actual need. Moreover, for a special case that the signal-to-noise (SNR power ratio is sufficiently high, we present an efficient transmission (ET policy and prove that the ET policy achieves the same performance with the ST policy. Finally, extensive simulations are conducted to evaluate the performance of the proposed policies and the impaction of various network parameters.

  16. A metamaterial electromagnetic energy rectifying surface with high harvesting efficiency

    Science.gov (United States)

    Duan, Xin; Chen, Xing; Zhou, Lin

    2016-12-01

    A novel metamaterial rectifying surface (MRS) for electromagnetic energy capture and rectification with high harvesting efficiency is presented. It is fabricated on a three-layer printed circuit board, which comprises an array of periodic metamaterial particles in the shape of mirrored split rings, a metal ground, and integrated rectifiers employing Schottky diodes. Perfect impedance matching is engineered at two interfaces, i.e. one between free space and the surface, and the other between the metamaterial particles and the rectifiers, which are connected through optimally positioned vias. Therefore, the incident electromagnetic power is captured with almost no reflection by the metamaterial particles, then channeled maximally to the rectifiers, and finally converted to direct current efficiently. Moreover, the rectifiers are behind the metal ground, avoiding the disturbance of high power incident electromagnetic waves. Such a MRS working at 2.45 GHz is designed, manufactured and measured, achieving a harvesting efficiency up to 66.9% under an incident power density of 5 mW/cm2, compared with a simulated efficiency of 72.9%. This high harvesting efficiency makes the proposed MRS an effective receiving device in practical microwave power transmission applications.

  17. On the Energy Conversion Efficiency of Piezoelectric Vibration Energy Harvesting Devices

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jae Eun [Catholic University of Daegu, Kyungsan (Korea, Republic of)

    2015-05-15

    To properly design and assess a piezoelectric vibration energy harvester, it is necessary to consider the application of an efficiency measure of energy conversion. The energy conversion efficiency is defined in this work as the ratio of the electrical output power to the mechanical input power for a piezoelectric vibration energy harvester with an impedance-matched load resistor. While previous research works employed the electrical output power for approximate impedance-matched load resistance, this work derives an efficiency measure considering optimally matched resistance. The modified efficiency measure is validated by comparing it with finite element analysis results for piezoelectric vibration energy harvesters with three different values of the electro-mechanical coupling coefficient. New findings on the characteristics of energy conversion and conversion efficiency are also provided for the two different impedance matching methods.

  18. Energy harvesting and wireless energy transmission for powering SHM sensor nodes

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, Stuart G [Los Alamos National Laboratory; Farinholt, Kevin M [Los Alamos National Laboratory; Park, Gyuhae [Los Alamos National Laboratory; Farrar, Charles R [Los Alamos National Laboratory

    2009-01-01

    In this paper, we present a feasibility study of using energy harvesting and wireless energy transmission systems to operate SHM sensor nodes. The energy harvesting approach examines the use of kinetic energy harvesters to scavenge energy from the ambient sources. Acceleration measurements were made on a bridge, and serve as the basis for a series of laboratory experiments that replicate these sources using an electromagnetic shaker. We also investigated the use of wireless energy transmission systems to operate SHM sensor nodes. The goal of this investigation is to develop SHM sensing systems which can be permanently embedded in the host structure and do not require on-board power sources. This paper summarizes considerations needed to design such systems, experimental procedures and results, and additional issues that can be used as guidelines for future investigations.

  19. Energy harvesting using AC machines with high effective pole count

    Science.gov (United States)

    Geiger, Richard Theodore

    In this thesis, ways to improve the power conversion of rotating generators at low rotor speeds in energy harvesting applications were investigated. One method is to increase the pole count, which increases the generator back-emf without also increasing the I2R losses, thereby increasing both torque density and conversion efficiency. One machine topology that has a high effective pole count is a hybrid "stepper" machine. However, the large self inductance of these machines decreases their power factor and hence the maximum power that can be delivered to a load. This effect can be cancelled by the addition of capacitors in series with the stepper windings. A circuit was designed and implemented to automatically vary the series capacitance over the entire speed range investigated. The addition of the series capacitors improved the power output of the stepper machine by up to 700%. At low rotor speeds, with the addition of series capacitance, the power output of the hybrid "stepper" was more than 200% that of a similarly sized PMDC brushed motor. Finally, in this thesis a hybrid lumped parameter / finite element model was used to investigate the impact of number, shape and size of the rotor and stator teeth on machine performance. A typical off-the-shelf hybrid stepper machine has significant cogging torque by design. This cogging torque is a major problem in most small energy harvesting applications. In this thesis it was shown that the cogging and ripple torque can be dramatically reduced. These findings confirm that high-pole-count topologies, and specifically the hybrid stepper configuration, are an attractive choice for energy harvesting applications.

  20. Power inversion design for ocean wave energy harvesting

    Science.gov (United States)

    Talebani, Anwar N.

    The needs for energy sources are increasing day by day because of several factors, such as oil depletion, and global climate change due to the higher level of CO2, so the exploration of various renewable energy sources is very promising area of study. The available ocean waves can be utilized as free source of energy as the water covers 70% of the earth surface. This thesis presents the ocean wave energy as a source of renewable energy. By addressing the problem of designing efficient power electronics system to deliver 5 KW from the induction generator to the grid with less possible losses and harmonics as possible and to control current fed to the grid to successfully harvest ocean wave energy. We design an AC-DC full bridge rectifier converter, and a DC-DC boost converter to harvest wave energy from AC to regulated DC. In order to increase the design efficiency, we need to increase the power factor from (0.5-0.6) to 1. This is accomplished by designing the boost converter with power factor correction in continues mode with RC circuit as an input to the boost converter power factor correction. This design results in a phase shift between the input current and voltage of the full bridge rectifier to generate a small reactive power. The reactive power is injected to the induction generator to maintain its functionality by generating a magnetic field in its stator. Next, we design a single-phase pulse width modulator full bridge voltage source DC-AC grid-tied mode inverter to harvest regulated DC wave energy to AC. The designed inverter is modulated by inner current loop, to control current injected to the grid with minimal filter component to maintain power quality at the grid. The simulation results show that our design successfully control the current level fed to the grid. It is noteworthy that the simulated efficiency is higher than the calculated one since we used an ideal switch in the simulated circuit.

  1. Inorganic electret with enhanced charge stability for energy harvesting

    DEFF Research Database (Denmark)

    Wang, Fei; Hansen, Ole

    2013-01-01

    We report a new surface treatment of inorganic electret materials which enhances the charge stability. Coating the surfaces with 1H, 1H, 2H, 2H - perfluorodecyltrichlorosilane (FDTS) makes the electret surface more hydrophobic which improves the surface charge stability under high humidity condit...... conditions. Thermal tests show that the thermal stability of charge in the inorganic electrets is also much better than that of polymer materials such as CYTOP. A demonstrator device with SiO2 electrets shows promising results for energy harvesting applications....

  2. Designing and Testing Energy Harvesters Suitable for Renewable Power Sources

    Science.gov (United States)

    Synkiewicz, B.; Guzdek, P.; Piekarski, J.; Zaraska, K.

    2016-01-01

    Energy harvesters convert waste power (heat, light and vibration) directly to electric power . Fast progress in their technology, design and areas of application (e.g. “Internet of Things”) has been observed recently. Their effectiveness is steadily growing which makes their application to powering sensor networks with wireless data transfer reasonable. The main advantage is the independence from wired power sources, which is especially important for monitoring state of environmental parameters. In this paper we describe the design and realization of a gas sensor monitoring CO level (powered by TEG) and two, designed an constructed in ITE, autonomous power supply modules powered by modern photovoltaic cells.

  3. Tunable Ultrasonic Energy Harvesting for Implantable Biosensors and Medical Devices

    Science.gov (United States)

    Pellegrino, M.; Eovino, B. E.; Beker, L.; Bourouina, T.; Lin, L.

    2016-11-01

    This work reports a tunable ultrasonic energy harvesting (UEH) device capable of high power output and/or large bandwidth based on concentric piezoelectric ring-shaped structures. Two different designs are presented: (1) the single ring-shaped UEH (r-UEH), and (2) concentric r-UEHs. Concentric r-UEHs can save space and therefore can provide benefits in powering low-power implantable biosensors and medical devices. This paper presents results of simulation studies and initial experiments of a single r-UEH.

  4. Reconfigurable RF Energy Harvester with Customized Differential PCB Antenna

    Directory of Open Access Journals (Sweden)

    Alessandro Bertacchini

    2015-11-01

    Full Text Available In this work, a Radio Frequency (RF Energy Harvester comprised of a differential Radio Frequency-to-Direct Current (RF-DC converter realized in ST130 nm Complementary Metal-Oxide-Semiconductor (CMOS technology and a customized broadband Printed Circuit Board (PCB antenna with inductive coupling feeding is presented. Experimental results show that the system can work with different carrier frequencies and thanks to its reconfigurable architecture the proposed converter is able to provide a regulated output voltage of 2 V over a 14 dB of RF input power range. The conversion efficiency of the whole system peaks at 18% under normal outdoor working conditions.

  5. Soap film flow visualization investigations of oscillating wing energy harvesters

    Science.gov (United States)

    Kirschmeier, Benjamin; Bryant, Matthew

    2015-03-01

    With increasing population and proliferation of wireless electronics, significant research attention has turned to harvesting energy from ambient sources such as wind and water flows at scales ranging from micro-watt to mega-watt levels. One technique that has recently attracted attention is the application of bio-inspired flapping wings for energy harvesting. This type of system uses a heaving and pitching airfoil to extract flow energy and generate electricity. Such a device can be realized using passive devices excited by aeroelastic flutter phenomena, kinematic mechanisms driven by mechanical linkages, or semi-active devices that are actively controlled in one degree of freedom and passively driven in another. For these types of systems, numerical simulations have showed strong dependence on efficiency and vortex interaction. In this paper we propose a new apparatus for reproducing arbitrary pitch-heave waveforms to perform flow visualization experiments in a soap film tunnel. The vertically falling, gravity driven soap film tunnel is used to replicate flows with a chord Reynolds number on the order of 4x104. The soap film tunnel is used to investigate leading edge vortex (LEV) and trailing edge vortex (TEV) interactions for sinusoidal and non-sinusoidal waveforms. From a qualitative analysis of the fluid structure interaction, we have been able to demonstrate that the LEVs for non-sinusoidal motion convect faster over the airfoil compared with sinusoidal motion. Signifying that optimal flapping frequency is dependent on the motion profile.

  6. An Energy Harvesting Underwater Acoustic Transmitter for Aquatic Animals

    Science.gov (United States)

    Li, Huidong; Tian, Chuan; Lu, Jun; Myjak, Mitchell J.; Martinez, Jayson J.; Brown, Richard S.; Deng, Zhiqun Daniel

    2016-09-01

    Acoustic telemetry is the primary method to actively track aquatic animals for behavioral studies. However, the small storage capacities of the batteries used in the transmitters limit the time that the implanted animals can be studied. In this research, we developed and implemented a battery-free acoustic transmitter that uses a flexible piezoelectric beam to harvest energy from fish swimming as the power source. The transmitter sends out a unique identification code with a sufficiently strong signal (150 dB, ref: 1 μPa at 1 meter) that has a detection range of up to 100 meters. Two prototypes, 100 mm and 77 mm long, respectively, weighing only about 1 gram or less in air, were sub-dermally implanted in two species of live fish. Transmissions were successfully detected as the fish swam in a natural manner. This represents the first known implanted energy-harvesting transmitter demonstrated in vivo. Successful development of this transmitter greatly expands the potential for long-term studies of the behaviors of aquatic animals and for subsequently developing strategies to mitigate the environmental impacts of renewable energy systems.

  7. An Energy Harvesting Underwater Acoustic Transmitter for Aquatic Animals

    Science.gov (United States)

    Li, Huidong; Tian, Chuan; Lu, Jun; Myjak, Mitchell J.; Martinez, Jayson J.; Brown, Richard S.; Deng, Zhiqun Daniel

    2016-01-01

    Acoustic telemetry is the primary method to actively track aquatic animals for behavioral studies. However, the small storage capacities of the batteries used in the transmitters limit the time that the implanted animals can be studied. In this research, we developed and implemented a battery-free acoustic transmitter that uses a flexible piezoelectric beam to harvest energy from fish swimming as the power source. The transmitter sends out a unique identification code with a sufficiently strong signal (150 dB, ref: 1 μPa at 1 meter) that has a detection range of up to 100 meters. Two prototypes, 100 mm and 77 mm long, respectively, weighing only about 1 gram or less in air, were sub-dermally implanted in two species of live fish. Transmissions were successfully detected as the fish swam in a natural manner. This represents the first known implanted energy-harvesting transmitter demonstrated in vivo. Successful development of this transmitter greatly expands the potential for long-term studies of the behaviors of aquatic animals and for subsequently developing strategies to mitigate the environmental impacts of renewable energy systems. PMID:27647426

  8. Ultrafast Energy Relaxation in Single Light-Harvesting Complexes

    CERN Document Server

    Malý, Pavel; Cogdell, Richard J; Mančal, Tomáš; van Grondelle, Rienk

    2015-01-01

    Energy relaxation in light-harvesting complexes has been extensively studied by various ultrafast spectroscopic techniques, the fastest processes being in the sub-100 fs range. At the same time much slower dynamics have been observed in individual complexes by single-molecule fluorescence spectroscopy (SMS). In this work we employ a pump-probe type SMS technique to observe the ultrafast energy relaxation in single light-harvesting complexes LH2 of purple bacteria. After excitation at 800 nm, the measured relaxation time distribution of multiple complexes has a peak at 95 fs and is asymmetric, with a tail at slower relaxation times. When tuning the excitation wavelength, the distribution changes in both its shape and position. The observed behaviour agrees with what is to be expected from the LH2 excited states structure. As we show by a Redfield theory calculation of the relaxation times, the distribution shape corresponds to the expected effect of Gaussian disorder of the pigment transition energies. By repe...

  9. Harvesting energy from the natural vibration of human walking.

    Science.gov (United States)

    Yang, Weiqing; Chen, Jun; Zhu, Guang; Yang, Jin; Bai, Peng; Su, Yuanjie; Jing, Qingsheng; Cao, Xia; Wang, Zhong Lin

    2013-12-23

    The triboelectric nanogenerator (TENG), a unique technology for harvesting ambient mechanical energy based on the triboelectric effect, has been proven to be a cost-effective, simple, and robust approach for self-powered systems. However, a general challenge is that the output current is usually low. Here, we demonstrated a rationally designed TENG with integrated rhombic gridding, which greatly improved the total current output owing to the structurally multiplied unit cells connected in parallel. With the hybridization of both the contact-separation mode and sliding electrification mode among nanowire arrays and nanopores fabricated onto the surfaces of two contact plates, the newly designed TENG produces an open-circuit voltage up to 428 V, and a short-circuit current of 1.395 mA with the peak power density of 30.7 W/m(2). Relying on the TENG, a self-powered backpack was developed with a vibration-to-electric energy conversion efficiency up to 10.62(±1.19) %. And it was also demonstrated as a direct power source for instantaneously lighting 40 commercial light-emitting diodes by harvesting the vibration energy from natural human walking. The newly designed TENG can be a mobile power source for field engineers, explorers, and disaster-relief workers.

  10. Ultrafast energy relaxation in single light-harvesting complexes.

    Science.gov (United States)

    Malý, Pavel; Gruber, J Michael; Cogdell, Richard J; Mančal, Tomáš; van Grondelle, Rienk

    2016-03-15

    Energy relaxation in light-harvesting complexes has been extensively studied by various ultrafast spectroscopic techniques, the fastest processes being in the sub-100-fs range. At the same time, much slower dynamics have been observed in individual complexes by single-molecule fluorescence spectroscopy (SMS). In this work, we use a pump-probe-type SMS technique to observe the ultrafast energy relaxation in single light-harvesting complexes LH2 of purple bacteria. After excitation at 800 nm, the measured relaxation time distribution of multiple complexes has a peak at 95 fs and is asymmetric, with a tail at slower relaxation times. When tuning the excitation wavelength, the distribution changes in both its shape and position. The observed behavior agrees with what is to be expected from the LH2 excited states structure. As we show by a Redfield theory calculation of the relaxation times, the distribution shape corresponds to the expected effect of Gaussian disorder of the pigment transition energies. By repeatedly measuring few individual complexes for minutes, we find that complexes sample the relaxation time distribution on a timescale of seconds. Furthermore, by comparing the distribution from a single long-lived complex with the whole ensemble, we demonstrate that, regarding the relaxation times, the ensemble can be considered ergodic. Our findings thus agree with the commonly used notion of an ensemble of identical LH2 complexes experiencing slow random fluctuations.

  11. Semi-flexible bimetal-based thermal energy harvesters

    CERN Document Server

    Boisseau, S; Monfray, S; Puscasu, O; Skotnicki, T; 10.1088/0964-1726/22/2/025021

    2013-01-01

    This paper introduces a new semi-flexible device able to turn thermal gradients into electricity by using a curved bimetal coupled to an electret-based converter. In fact, a two-steps conversion is carried out: (i) a curved bimetal turns the thermal gradient into a mechanical oscillation that is then (ii) converted into electricity thanks to an electrostatic converter using electrets in Teflon (r). The semi-flexible and low cost design of these new energy converters pave the way to mass production over large areas of thermal energy harvesters. Raw output powers up to 13.46uW per device were reached on a hot source at 60{\\deg}C and forced convection. Then, a DC-to-DC flyback converter has been sized to turn the energy harvesters' raw output powers into a viable supply source for an electronic circuit (DC-3V). At the end, 10uW of directly usable output power were reached with 3 devices, which is compatible with Wireless Sensor Networks powering applications. Please cite as : S Boisseau et al 2013 Smart Mater. S...

  12. CH2 Energy Harvesting Systems: Economic Use and Efficiency

    Directory of Open Access Journals (Sweden)

    Chun Cheung

    2012-11-01

    Full Text Available This paper looks at the City of Melbourne's new office development CH2 as a case study of world class energy performance. In particular, the integrated design of conventionally independent systems has led to the potential to deliver significant savings to the Council and to deliver better environmental conditions to building occupants that in turn may contribute to satisfaction, well-being and productivity. It is concluded that this project has the potential to be an iconic example of effective implementation of ESD (environmental sustainable design principles and therefore act as a demonstration project to others. Energy efficiency of more than 50% of current benchmarks for Melbourne is effected. Energy harvesting is defined as arising from squander, waste and nature, which is a new concept introduced in this paper to better describe the design decision process.

  13. Flexible Nanogenerators for Energy Harvesting and Self-Powered Electronics.

    Science.gov (United States)

    Fan, Feng Ru; Tang, Wei; Wang, Zhong Lin

    2016-06-01

    Flexible nanogenerators that efficiently convert mechanical energy into electrical energy have been extensively studied because of their great potential for driving low-power personal electronics and self-powered sensors. Integration of flexibility and stretchability to nanogenerator has important research significance that enables applications in flexible/stretchable electronics, organic optoelectronics, and wearable electronics. Progress in nanogenerators for mechanical energy harvesting is reviewed, mainly including two key technologies: flexible piezoelectric nanogenerators (PENGs) and flexible triboelectric nanogenerators (TENGs). By means of material classification, various approaches of PENGs based on ZnO nanowires, lead zirconate titanate (PZT), poly(vinylidene fluoride) (PVDF), 2D materials, and composite materials are introduced. For flexible TENG, its structural designs and factors determining its output performance are discussed, as well as its integration, fabrication and applications. The latest representative achievements regarding the hybrid nanogenerator are also summarized. Finally, some perspectives and challenges in this field are discussed.

  14. Parametric dependence of energy harvesting performance with an oscillating hydrofoil

    Science.gov (United States)

    Strom, Benjamin; Kim, Daegyoum; Mandre, Shreyas; Breuer, Kenneth

    2014-11-01

    We report on experiments on tidal energy conversion from a open channel water flow using an oscillating hydrofoil. The hydrofoil is operated at high angles of attack such that the formation and capture of a leading edge vortex greatly enhances the energy conversion efficiency. A computer-controlled pitch and heave system allows for arbitrary position profiles to be imposed. Force and torque measurements are used to determine the energy harvesting efficiency as a function of Reynolds number, pitch and heave amplitudes, phase shift, the location of the pitching axis, position profile, and the cross sectional shape of the hydrofoil. PIV measurements are used to capture the vortex dynamics and these results are compared to the computational results of Frank and Franck (2013). Efficiency was found to be most sensitive to pitch amplitude, pitching axis and phase shift with relatively little dependence on Reynolds number, heave amplitude, and foil shape. Work supported by DOE-ARPAe.

  15. Harvesting Ambient Environmental Energy for Wireless Sensor Networks: A Survey

    Directory of Open Access Journals (Sweden)

    Gongbo Zhou

    2014-01-01

    Full Text Available In recent years, wireless sensor networks (WSNs have grown dramatically and made a great progress in many applications. But having limited life, batteries, as the power sources of wireless sensor nodes, have restricted the development and application of WSNs which often requires a very long lifespan for better performance. In order to make the WSNs prevalent in our lives, an alternative energy source is required. Environmental energy is an attractive power source, and it provides an approach to make the sensor nodes self-powered with the possibility of an almost infinite lifetime. The goal of this survey is to present a comprehensive review of the recent literature on the various possible energy harvesting technologies from ambient environment for WSNs.

  16. Global stabilization of high-energy response of a nonlinear wideband electromagnetic energy harvester

    Science.gov (United States)

    Sato, T.; Kato, S.; Masuda, A.

    2016-09-01

    This paper presents a resonance-type vibration energy harvester with a Duffing-type nonlinear oscillator which is designed to perform effectively in a wide frequency band. For the conventional linear vibration energy harvester, the maximum performance of the power generation and its bandwidth are in a relation of trade-off. Introducing a Duffing-type nonlinearity can expand the resonance frequency band and enable the harvester to generate larger electric power in a wider frequency range. However, since such nonlinear oscillator may have coexisting multiple steady-state solutions in the resonance band, it is difficult for the nonlinear harvester to maintain the high performance of the power generation constantly. The principle of self-excitation and entrainment has been utilized to give global stability to the high-energy orbit by destabilizing other unexpected low-energy orbits by introducing a switching circuit of the load resistance between positive and the negative values depending on the response amplitude of the oscillator. In this paper, an improved control law that switches the load resistance according to a frequency-dependent threshold is proposed to ensure the oscillator to respond in the high-energy orbit without ineffective power consumption. Numerical study shows that the steady-state responses of the harvester with the proposed control low are successfully kept on the high-energy orbit without repeating activation of the excitationmode.

  17. Hydrogen based energy storage for energy harvesting systems

    Energy Technology Data Exchange (ETDEWEB)

    Bretthauer, Christian

    2011-07-01

    This thesis presents the development of a novel type of silicon integrated alkaline fuel cell - electrolyser device as on-chip energy storage. The alkaline environment allows not only a facilitated water management compared to state-of-the-art acidic integrated fuel cell systems, it further allows the usage of non-precious metal catalysts and hydrogen storage materials, for the first time. Additionally, a button cell shaped version of the accumulator is presented that incorporates a photoactive SrTiO{sub 3} ceramic for solar recharge. The solar charging mechanism is shown to be inherently self-regulating such that the cell depicts essentially a Micro Hydrogen Economy including energy conversion, energy management and energy storage in a single device. (orig.)

  18. Kinematics and Dynamics of a Tensegrity-Based Water Wave Energy Harvester

    Directory of Open Access Journals (Sweden)

    Min Lin

    2016-01-01

    Full Text Available A tensegrity-based water wave energy harvester is proposed. The direct and inverse kinematic problems are investigated by using a geometric method. Afterwards, the singularities and workspaces are discussed. Then, the Lagrangian method was used to develop the dynamic model considering the interaction between the harvester and water waves. The results indicate that the proposed harvester allows harvesting 13.59% more energy than a conventional heaving system. Therefore, tensegrity systems can be viewed as one alternative solution to conventional water wave energy harvesting systems.

  19. Conductive Elastomers for Stretchable Electronics, Sensors and Energy Harvesters

    Directory of Open Access Journals (Sweden)

    Jin-Seo Noh

    2016-04-01

    Full Text Available There have been a wide variety of efforts to develop conductive elastomers that satisfy both mechanical stretchability and electrical conductivity, as a response to growing demands on stretchable and wearable devices. This article reviews the important progress in conductive elastomers made in three application fields of stretchable technology: stretchable electronics, stretchable sensors, and stretchable energy harvesters. Diverse combinations of insulating elastomers and non-stretchable conductive materials have been studied to realize optimal conductive elastomers. It is noted that similar material combinations and similar structures have often been employed in different fields of application. In terms of stretchability, cyclic operation, and overall performance, fields such as stretchable conductors and stretchable strain/pressure sensors have achieved great advancement, whereas other fields like stretchable memories and stretchable thermoelectric energy harvesting are in their infancy. It is worth mentioning that there are still obstacles to overcome for the further progress of stretchable technology in the respective fields, which include the simplification of material combination and device structure, securement of reproducibility and reliability, and the establishment of easy fabrication techniques. Through this review article, both the progress and obstacles associated with the respective stretchable technologies will be understood more clearly.

  20. Improving thermoelectric energy harvesting efficiency by using graphene

    Directory of Open Access Journals (Sweden)

    Muhammad Usman

    2016-05-01

    Full Text Available This study is aimed at enhancing the efficiency of a thermoelectric (TE energy harvesting system by using a thick graphene layer. This method is a simple yet effective way to increase the temperature gradient across a conventional TE module by accelerating heat dissipation on the cold side of the system. Aqueous dispersions of graphene were used to prepare a 112-μm thick graphene layer on the cold side of the TE system with aluminum as the substrate material. The maximum efficiency of the proposed system was improved by 25.45 %, as compared to the conventional TE system, which does not have a graphene layer. Additionally, the proposed system shows very little performance deterioration (2.87 % in the absence of enough air flow on the cold side of the system, compared to the case of the conventional system (10.59 %. Hence, the proposed system, when coupled with the latest research on high performance TE materials, presents a groundbreaking improvement in the practical application of the TE energy harvesting systems.

  1. Vibration piezoelectric energy harvester with multi-beam

    Directory of Open Access Journals (Sweden)

    Yan Cui

    2015-04-01

    Full Text Available This work presents a novel vibration piezoelectric energy harvester, which is a micro piezoelectric cantilever with multi-beam. The characteristics of the PZT (Pb(Zr0.53Ti0.47O3 thin film were measured; XRD (X-ray diffraction pattern and AFM (Atomic Force Microscope image of the PZT thin film were measured, and show that the PZT (Pb(Zr0.53Ti0.47O3 thin film is highly (110 crystal oriented; the leakage current is maintained in nA magnitude, the residual polarisation Pr is 37.037 μC/cm2, the coercive field voltage Ec is 27.083 kV/cm, and the piezoelectric constant d33 is 28 pC/N. In order to test the dynamic performance of the energy harvester, a new measuring system was set up. The maximum output voltage of the single beam of the multi-beam can achieve 80.78 mV under an acceleration of 1 g at 260 Hz of frequency; the maximum output voltage of the single beam of the multi-beam is almost 20 mV at 1400 Hz frequency.

  2. Vibration piezoelectric energy harvester with multi-beam

    Energy Technology Data Exchange (ETDEWEB)

    Cui, Yan, E-mail: yanc@dlut.edu.cn; Zhang, Qunying, E-mail: zhangqunying89@126.com; Yao, Minglei, E-mail: yaomingleiok@126.com [Key Laboratory for Precision and Non-traditional Machining Technology of the Ministry of Education, Dalian University of Technology, 116024, Dalian, Liaoning Province (China); Dong, Weijie, E-mail: dongwj@dlut.edu.cn [School of Electronic and Information Engineering, Dalian University of Technology, 116024, Dalian, Liaoning Province (China); Gao, Shiqiao, E-mail: gaoshq@bit.edu.cn [State Key Laboratory of Explosion Science and Technology, Beijing Institute of Technology, 100081, Beijing Province (China)

    2015-04-15

    This work presents a novel vibration piezoelectric energy harvester, which is a micro piezoelectric cantilever with multi-beam. The characteristics of the PZT (Pb(Zr{sub 0.53}Ti{sub 0.47})O{sub 3}) thin film were measured; XRD (X-ray diffraction) pattern and AFM (Atomic Force Microscope) image of the PZT thin film were measured, and show that the PZT (Pb(Zr{sub 0.53}Ti{sub 0.47})O{sub 3}) thin film is highly (110) crystal oriented; the leakage current is maintained in nA magnitude, the residual polarisation Pr is 37.037 μC/cm{sup 2}, the coercive field voltage Ec is 27.083 kV/cm, and the piezoelectric constant d{sub 33} is 28 pC/N. In order to test the dynamic performance of the energy harvester, a new measuring system was set up. The maximum output voltage of the single beam of the multi-beam can achieve 80.78 mV under an acceleration of 1 g at 260 Hz of frequency; the maximum output voltage of the single beam of the multi-beam is almost 20 mV at 1400 Hz frequency. .

  3. Energy harvesting to power embedded condition monitoring hardware

    Science.gov (United States)

    Farinholt, Kevin; Brown, Nathan; Siegel, Jake; McQuown, Justin; Humphris, Robert

    2015-04-01

    The shift toward condition-based monitoring is a key area of research for many military, industrial, and commercial customers who want to lower the overall operating costs of capital equipment and general facilities. Assessing the health of rotating systems such as gearboxes, bearings, pumps and other actuation systems often rely on the need for continuous monitoring to capture transient signals that are evidence of events that could cause (i.e. cavitation), or be the result of (i.e. spalling), damage within a system. In some applications this can be accomplished using line powered analyzers, however for wide-spread monitoring, the use of small-scale embedded electronic systems are more desirable. In such cases the method for powering the electronics becomes a significant design factor. This work presents a multi-source energy harvesting approach meant to provide a robust power source for embedded electronics, capturing energy from vibration, thermal and light sources to operate a low-power sensor node. This paper presents the general design philosophy behind the multi-source harvesting circuit, and how it can be extended from powering electronics developed for periodic monitoring to sensing equipment capable of providing continuous condition-based monitoring.

  4. Improper Ferroelectricity in Stuffed Aluminate Sodalites for Pyroelectric Energy Harvesting

    Science.gov (United States)

    Maeda, Yusaku; Wakamatsu, Toru; Konishi, Ayako; Moriwake, Hiroki; Moriyoshi, Chikako; Kuroiwa, Yoshihiro; Tanabe, Kenji; Terasaki, Ichiro; Taniguchi, Hiroki

    2017-03-01

    In the present study, we demonstrate ferroelectricity in stuffed aluminate sodalites (Ca1 -xSrx)8[AlO2]12(WO4)2 (x ≤0.2 ) (C1 -xSxAW ). Pyroelectric measurements clarify switchable spontaneous polarization in polycrystalline C1 -xSxAW , whose polarization values are on the order of 10-2 μ C /cm2 at room temperature. A weak anomaly in the dielectric permittivity at temperatures near the ferroelectric transition temperature suggests improper ferroelectricity of C1 -xSxAW for all investigated values of x . A comprehensive study involving synchrotron x-ray powder diffraction measurements, molecular dynamics simulations, and first-principles calculations clarifies that the ferroelectric phase transition of C1 -xSxAW is driven by the freezing of the fluctuations of WO4 tetrahedra in the voids of an [AlO2]12 12 - framework. The voltage response and electromechanical coupling factor of C1 -xSxAW estimated from the present results indicate that this material exhibits excellent performance as a pyroelectric energy harvester, suggesting that aluminate sodalites exhibit great promise as a class of materials for highly efficient energy-harvesting devices.

  5. Proof mass effects on spiral electrode d33 mode piezoelectric diaphragm-based energy harvester

    KAUST Repository

    Shen, Zhiyuan

    2013-01-01

    This paper presents the characterization of an energy harvester using a piezoelectric diaphragm as the vibration energy conversion microstructure. The diaphragm containing the spiral electrode operates in the d33 mode. The energy harvesting performance of the diaphragm was characterized. The optimal resistance load and the working frequency were characterized. The resonance tuning and the energy harvesting enhancement due to a proof mass were verified. © 2013 IEEE.

  6. GreenDelivery: Proactive Content Caching and Push with Energy-Harvesting-based Small Cells

    OpenAIRE

    Zhou, Sheng; Gong, Jie; ZHOU, Zhenyu; Chen, Wei; Niu, Zhisheng

    2015-01-01

    The explosive growth of mobile multimedia traffic calls for scalable wireless access with high quality of service and low energy cost. Motivated by the emerging energy harvesting communications, and the trend of caching multimedia contents at the access edge and user terminals, we propose a paradigm-shift framework, namely GreenDelivery, enabling efficient content delivery with energy harvesting based small cells. To resolve the two-dimensional randomness of energy harvesting and content requ...

  7. An energy harvesting system surveyed for a variety of unattended electronic applications

    Science.gov (United States)

    Zhao, Wei; Choi, Kwangsik; Bauman, Scott; Salter, Thomas; Lowy, Daniel A.; Peckerar, Martin; Khandani, Mehdi Kalantari

    2013-01-01

    All energy-harvesting schemes require some form of "intermediate" storage - batteries or capacitors that reservoir energy harvested from the environment. There are a number of reasons for this requirement. Ambient energy fluctuates and intermediate storage smoothes out the impact of these fluctuations on the power delivered to a load. In addition, energy must be "conditioned" to be useful in a given application. It must be set to a certain voltage or made capable of delivering a desired current to load. In this article, a complete energy harvesting system including storage and conditioning electronics is described with a concentration on radio frequency (RF) harvesting. The system is capable of harvesting energy from a commercially available hand-held communication device, and exhibits an overall energy harvesting efficiency of 13.2%. Several potential applications have been investigated based on the performance of this system. Highlighted example applications include power sources for nodes in an architectural structural integrity monitor, and limb prosthesis.

  8. Design and fabrication of a micro electromagnetic vibration energy harvester

    Institute of Scientific and Technical Information of China (English)

    Wang Peng; Li Wei; Che Lufeng

    2011-01-01

    This paper presents a new micro electromagnetic energy harvester that can convert transverse vibration energy to electrical power.It mainly consists of folded beams,a permanent magnet and copper planar coils.The calculated value of the natural frequency is 274 Hz and electromagnetic simulation shows that the magnetic flux density will decrease sharply with increasing space between the magnet and coils.A prototype has been fabricated using MEMS micromachining technology.The testing results show that at the resonant frequency of 242 Hz,the prototype can generate 0.55 μW of maximal output power with peak-peak voltage of 28 mV for 0.5g (g =9.8 m/s2) external acceleration.

  9. Improvement of Pyroelectric Cells for Thermal Energy Harvesting

    Directory of Open Access Journals (Sweden)

    Jing-Chih Ciou

    2012-01-01

    Full Text Available This study proposes trenching piezoelectric (PZT material in a thicker PZT pyroelectric cell to improve the temperature variation rate to enhance the efficiency of thermal energy-harvesting conversion by pyroelectricity. A thicker pyroelectric cell is beneficial in generating electricity pyroelectrically, but it hinders rapid temperature variations. Therefore, the PZT sheet was fabricated to produce deeper trenches to cause lateral temperature gradients induced by the trenched electrode, enhancing the temperature variation rate under homogeneous heat irradiation. When the trenched electrode type with an electrode width of 200 μm and a cutting depth of 150 μm was used to fabricate a PZT pyroelectric cell with a 200 μm thick PZT sheet, the temperature variation rate was improved by about 55%. Therefore, the trenched electrode design did indeed enhance the temperature variation rate and the efficiency of pyroelectric energy converters.

  10. Integrated Solar-Energy-Harvesting and -Storage Device

    Science.gov (United States)

    whitacre, Jay; Fleurial, Jean-Pierre; Mojarradi, Mohammed; Johnson, Travis; Ryan, Margaret Amy; Bugga, Ratnakumar; West, William; Surampudi, Subbarao; Blosiu, Julian

    2004-01-01

    A modular, integrated, completely solid-state system designed to harvest and store solar energy is under development. Called the power tile, the hybrid device consists of a photovoltaic cell, a battery, a thermoelectric device, and a charge-control circuit that are heterogeneously integrated to maximize specific energy capacity and efficiency. Power tiles could be used in a variety of space and terrestrial environments and would be designed to function with maximum efficiency in the presence of anticipated temperatures, temperature gradients, and cycles of sunlight and shadow. Because they are modular in nature, one could use a single power tile or could construct an array of as many tiles as needed. If multiple tiles are used in an array, the distributed and redundant nature of the charge control and distribution hardware provides an extremely fault-tolerant system. The figure presents a schematic view of the device.

  11. Experiment and modeling of a two-dimensional piezoelectric energy harvester

    Science.gov (United States)

    Yang, Yaowen; Wu, Hao; Kiong Soh, Chee

    2015-12-01

    Vibration energy harvesting using piezoelectric materials has attracted much research interest in recent years. Numerous efforts have been devoted to improving the efficiency of vibration energy harvesters and broadening their bandwidths. In most reported literature, energy harvesters are designed to harvest energy from vibration source with a specific excitation direction. However, a practical environmental vibration source may include multiple components from different directions. Thus, it is an important concern to design a vibration energy harvester to be adaptive to multiple excitation directions. In this article, a piezoelectric energy harvester with frame configuration is proposed to achieve two-dimensional (2D) vibration energy harvesting. The harvester works in two fundamental modes, i.e., its vertical and horizontal vibration modes. By tuning the structural parameters, the harvester can capture vibration energy from arbitrary directions in a 2D plane. Experimental studies are carried out to prove its feasibility. A finite element model and an equivalent circuit model are built to simulate the system and validate the experiment outcomes. The study of this 2D energy harvester indicates its promising potential in practical vibration scenarios.

  12. Incident flow effects on the performance of piezoelectric energy harvesters from galloping vibrations

    Directory of Open Access Journals (Sweden)

    Abdessattar Abdelkefi

    2014-01-01

    Full Text Available In this paper, we investigate experimentally the concept of energy harvesting from galloping oscillations with a focus on wake and turbulence effects. The harvester is composed of a unimorph piezoelectric cantilever beam with a square cross-section tip mass. In one case, the harvester is placed in the wake of another galloping harvester with the objective of determining the wake effects on the response of the harvester. In the second case, meshes were placed upstream of the harvester with the objective of investigating the effects of upstream turbulence on the response of the harvester. The results show that both wake effects and upstream turbulence significantly affect the response of the harvester. Depending on the spacing between the two squares and the opening size of the mesh, wake and upstream turbulence can positively enhance the level of the harvested power.

  13. Preliminary Performance Evaluation of MEMS-based Piezoelectric Energy Harvesters in Extended Temperature Range

    DEFF Research Database (Denmark)

    Xu, R.; Borregaard, L.M.; Lei, A.

    2012-01-01

    In this work a batch of MEMS-based vibration energy harvesters consisting of a silicon/PZT thick film ntilever with integrated proof mass is characterized. The purpose of a vibration energy harvester is to convert low grade vibrations to useful electrical power. Optimally, the natural frequency...... of the harvester should match the frequency of he ambient vibration. The first step to achieve this is to evaluate the uniformity of the fabricated harvesters and nderstand the effects of temperature on the harvesters during operation. Therefore, the uniformity of 40 energy harvesters from one wafer has been...... evaluated. Thereafter the performance of the energy harvesters operating at emperatures between -30°C to 100°C was measured....

  14. 3D, wideband vibro-impacting-based piezoelectric energy harvester

    Directory of Open Access Journals (Sweden)

    Qiangmo Yu

    2015-04-01

    Full Text Available An impacting-based piezoelectric energy harvester was developed to address the limitations of the existing approaches in single-dimensional operation as well as a narrow working bandwidth. In the harvester, a spiral cylindrical spring rather than the conventional thin cantilever beam was utilized to extract the external vibration with arbitrary directions, which has the capability to impact the surrounding piezoelectric beams to generate electricity. And the introduced vibro-impacting between the spiral cylindrical spring and multi-piezoelectric-beams resulted in not only a three-dimensional response to external vibration, but also a bandwidth-broadening behavior. The experimental results showed that each piezoelectric beam exhibited a maximum bandwidth of 8 Hz and power of 41 μW with acceleration of 1 g (with g=9.8 ms−2 along the z-axis, and corresponding average values of 5 Hz and 45 μW with acceleration of 0.6 g in the x-y plane.

  15. 3D, wideband vibro-impacting-based piezoelectric energy harvester

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Qiangmo; Yang, Jin, E-mail: yangjin@cqu.edu.cn; Yue, Xihai; Yang, Aichao; Zhao, Jiangxin; Zhao, Nian; Wen, Yumei; Li, Ping [Department of Optoelectronic Engineering, Research Center of Sensors and Instruments, Chongqing University, Chongqing 400044 (China)

    2015-04-15

    An impacting-based piezoelectric energy harvester was developed to address the limitations of the existing approaches in single-dimensional operation as well as a narrow working bandwidth. In the harvester, a spiral cylindrical spring rather than the conventional thin cantilever beam was utilized to extract the external vibration with arbitrary directions, which has the capability to impact the surrounding piezoelectric beams to generate electricity. And the introduced vibro-impacting between the spiral cylindrical spring and multi-piezoelectric-beams resulted in not only a three-dimensional response to external vibration, but also a bandwidth-broadening behavior. The experimental results showed that each piezoelectric beam exhibited a maximum bandwidth of 8 Hz and power of 41 μW with acceleration of 1 g (with g=9.8 ms{sup −2}) along the z-axis, and corresponding average values of 5 Hz and 45 μW with acceleration of 0.6 g in the x-y plane. .

  16. Compressed Air Energy Storage System Control and Performance Assessment Using Energy Harvested Index

    Directory of Open Access Journals (Sweden)

    Hanif SedighNejad

    2014-01-01

    Full Text Available In this paper a new concept for control and performance assessment of compressed air energy storage (CAES systems in a hybrid energy system is introduced. The proposed criterion, based on the concept of energy harvest index (HEI, measures the capability of a storage system to capture renewable energy. The overall efficiency of the CAES system and optimum control and design from the technical and economic point of view is presented. A possible application of this idea is an isolated community with significant wind energy resource. A case study reveals the usefulness of the proposed criterion in design, control and implementation of a small CAES system in a hybrid power system (HPM for an isolated community. Energy harvested index and its effectiveness in increasing the wind penetration rate in the total energy production is discussed.

  17. Smart metacomposite-based systems for transient elastic wave energy harvesting

    Science.gov (United States)

    Yi, K.; Monteil, M.; Collet, M.; Chesne, S.

    2017-03-01

    In this paper, novel harvesting systems are proposed and studied to obtain enhanced energy from transient waves. Each of these systems contains a piezo-lens to focus waves and a harvester to yield energy from the induced focused waves. The piezo-lens comprises a host plate and piezoelectric patches bonded on the plate surfaces. The piezoelectric patches are shunted with negative capacitance (NC) circuits in order to control the spatial variation of the effective refractive index inside the piezo-lens domain. The harvester is placed at the designed focal point of the piezo-lens, two different synchronized switch harvesting on inductor (SSHI) based harvesters are analyzed in the studies. Corrected reduced models are developed to predict the transient responses of the harvesting systems. The performances of the systems incorporating SSHI-based harvesters in transient wave energy harvesting are studied and compared with the system using a standard DC harvester. The focusing effect of the piezo-lens on transient waves and its capability to improve the harvested energy are verified. Since the NC circuits are active elements, an energy balance analysis is performed. Applicability of the harvesting systems is also discussed.

  18. Chaos control applied to piezoelectric vibration-based energy harvesting systems

    Science.gov (United States)

    Barbosa, W. O. V.; De Paula, A. S.; Savi, M. A.; Inman, D. J.

    2015-11-01

    Chaotic behavior presents intrinsic richness due to the existence of an infinity number of unstable periodic orbits (UPOs). The possibility of stabilizing these periodic patterns with a small amount of energy makes this kind of response interesting to various dynamical systems. Energy harvesting has as a goal the use of available mechanical energy by promoting a conversion into electrical energy. The combination of these two approaches may establish autonomous systems where available environmental mechanical energy can be employed for control purposes. Two different goals can be defined as priority, allowing a change between them: vibration reduction and energy harvesting enhancement. This work deals with the use of harvested energy to perform chaos control. Both control actuation and energy harvesting are induced employing piezoelectric materials, in a simultaneous way. A bistable piezomagnetoelastic structure subjected to harmonic excitations is investigated as a case study. Numerical simulations show situations where it is possible to perform chaos control using only the energy generated by the harvesting system.

  19. Performance of a Piezoelectric Energy Harvester under Vibrations Taken from a Helicopter

    OpenAIRE

    Zhu, Dibin; Beeby, Steve; Tudor, John; Grabham, Neil; White, Neil; Harris, Nick

    2011-01-01

    This paper compares performance of a piezoelectric vibration energy harvester, in terms of output power, under different types of vibration. The most common method used to characterize a vibration energy harvester is to excite the energy harvester under a sinusoidal vibration of its resonant frequency and measure the voltage across certain electrical loads. However, in practical applications, the vibration spectrum usually contains multiple peaks at different frequencies. In this research, a ...

  20. Conversion efficiency of an energy harvester based on resonant tunneling through quantum dots with heat leakage

    Science.gov (United States)

    Kano, Shinya; Fujii, Minoru

    2017-03-01

    We study the conversion efficiency of an energy harvester based on resonant tunneling through quantum dots with heat leakage. Heat leakage current from a hot electrode to a cold electrode is taken into account in the analysis of the harvester operation. Modeling of electrical output indicates that a maximum heat leakage current is not negligible because it is larger than that of the heat current harvested into electrical power. A reduction of heat leakage is required in this energy harvester in order to obtain efficient heat-to-electrical conversion. Multiple energy levels of a quantum dot can increase the output power of the harvester. Heavily doped colloidal semiconductor quantum dots are a possible candidate for a quantum-dot monolayer in the energy harvester to reduce heat leakage, scaling down device size, and increasing electrical output via multiple discrete energy levels.

  1. Power Management Integrated Circuit for Indoor Photovoltaic Energy Harvesting System

    Science.gov (United States)

    Jain, Vipul

    In today's world, power dissipation is a main concern for battery operated mobile devices. Key design decisions are being governed by power rather than area/delay because power requirements are growing more stringent every year. Hence, a hybrid power management system is proposed, which uses both a solar panel to harvest energy from indoor lighting and a battery to power the load. The system tracks the maximum power point of the solar panel and regulates the battery and microcontroller output load voltages through the use of an on-chip switched-capacitor DC-DC converter. System performance is verified through simulation at the 180nm technology node and is made to be integrated on-chip with 0.25 second startup time, 79% efficiency, --8/+14% ripple on the load, an average 1micro A of quiescent current (3.7micro W of power) and total on-chip area of 1.8mm2 .

  2. High efficiency nanostructured thin film solar cells for energy harvesting

    Science.gov (United States)

    Welser, Roger E.; Sood, Ashok K.; Lewis, Jay S.; Dhar, Nibir K.; Wijewarnasuriya, Priyalal S.

    2016-05-01

    Thin-film III-V materials are an attractive candidate material for solar energy harvesting devices capable of supplying portable and mobile power in both terrestrial and space environments. Nanostructured quantum well and quantum dot solar cells are being widely investigated as a means of extending infrared absorption and enhancing photovoltaic device performance. In this paper, we will review recent progress on realizing high-voltage InGaAs/GaAs quantum well solar cells that operate at or near the radiative limit of performance. These high-voltage nanostructured device designs provide a pathway to enhance the performance of existing device technologies, and can also be leveraged for next-generation solar cells.

  3. Security Issues of Solar Energy Harvesting Road Side Unit (RSU

    Directory of Open Access Journals (Sweden)

    Qutaiba I. Ali

    2015-06-01

    Full Text Available Vehicular network security had spanned and covered a wide range of security related issues. Howeversolar energy harvesting Road Side Unit (RSU security was not defined clearly, it is this aspect that is considered in this paper. In this work, we will suggest an RSU security model to protect it against different internal and external threats. The main goal is to protect RSU specific data (needed for its operation as well as its functionality and accessibility. The suggested RSU security model must responds to many objectives, it should ensure that the administrative information exchanged is correct and undiscoverable (information authenticity and privacy, the source (e.g., VANET server is who he claims to be (message integrity and source authentication and the system is robust and available (using Intrusion Detection System (IDS. In this paper, we suggest many techniques to strength RSU security and they were prototyped using an experimental model based on Ubicom IP2022 network processor development kit .

  4. New DRIE-Patterned Electrets for Vibration Energy Harvesting

    Directory of Open Access Journals (Sweden)

    Chaillout J.-J.

    2012-10-01

    Full Text Available This paper is about a new manufacturing process aimed at developing stable SiO2/Si3N4 patterned electrets using a Deep Reactive Ion Etching (DRIE step for an application in electret-based Vibration Energy Harvesters (e-VEH. This process consists in forming continuous layers of SiO2/Si3N4 electrets in order to limit surface conduction phenomena and is a new way to see the problem of electret patterning. Experimental results prove that patterned electrets charged by a positive corona discharge show excellent stability with high surface charge densities that may reach 5mC/m2 on 1.1μm-thick layers, even with fine patterning and harsh temperature conditions (up to 250°C. This paves the way to new e-VEH designs and manufacturing processes.

  5. Analytical Modelling of a Plucked Piezoelectric Bimorph for Energy Harvesting

    CERN Document Server

    Pozzi, Michele

    2012-01-01

    Energy harvesting (EH) is a multidisciplinary research area, involving physics, materials science and engineering, with the objective of providing renewable sources of sufficient power to operate targeted low-power applications. Piezoelectric transducers are often used for vibrational, inertial and direct movement EH. One problem is that, due to the stiffness of the most common material (PZT) and typically useful sizes, intrinsic resonant frequencies are normally high, whereas the available power is often concentrated at low frequencies. The aim of the plucking technique of frequency up-conversion, also known as "pizzicato" excitation, is to bridge this frequency gap. In this paper, the technique is modelled analytically. The analytical model is developed starting from the Euler-Bernoulli beam equations modified for piezoelectric coupling. A system of differential equations and associated initial conditions are derived which describe the free vibration of a piezoelectric bimorph in the last part of the plucki...

  6. Homotopy analysis approach for nonlinear piezoelectric vibration energy harvesting

    Directory of Open Access Journals (Sweden)

    Shahlaei-Far Shahram

    2016-01-01

    Full Text Available Piezoelectric energy harvesting from a vertical geometrically nonlinear cantilever beam with a tip mass subject to transverse harmonic base excitations is analyzed. One piezoelectric patch is placed on the slender beam to convert the tension and compression into electrical voltage. Applying the homotopy analysis method to the coupled electromechanical governing equations, we derive analytical solutions for the horizontal displacement of the tip mass and consequently the output voltage from the piezoelectric patch. Analytical approximation for the frequency response and phase of the geometrically forced nonlinear vibration system are also obtained. The research aims at a rigorous analytical perspective on a nonlinear problem which has previously been solely investigated by numerical and experimental methods.

  7. Comparative Study of Antenna Designs for RF Energy Harvesting

    Directory of Open Access Journals (Sweden)

    Sika Shrestha

    2013-01-01

    Full Text Available In the last few years, several antenna designs of rectenna that meet various objectives have been proposed for use in RF energy harvesting. Among various antennas, microstrip patch antennas are widely used because of their low profile, light weight, and planar structure. Conventional patch antennas are rectangular or circular in shape, but variations in their basic design are made for different purposes. This paper begins with an explanation and discussion of different designs, put forward with an aim of miniaturization, harmonic rejection, and reconfigurability. Finally, microstrip patch structured rectennas are evaluated and compared with an emphasis on the various methods adopted to obtain a compact rectenna, harmonic rejection functionality, and frequency and polarization selectivity.

  8. Infrared Solar Energy Harvesting using Nano-Rectennas

    CERN Document Server

    Sayed, Islam E Hashem

    2015-01-01

    Rectennas formed from nanodipole antennas terminated by plasmonic metal-insulator-metal (MIM) travelling wave transmission line rectifiers are developed for ambient thermal energy harvesting at 30 THz. The transmission lines are formed from two strips coupled either vertically or laterally. A systematic design approach is presented, that shows how different components can be integrated with each other with maximum radiation receiving nantenna efficiency, maximum coupling efficiency between nantenna and rectifier, and maximum MIM diode rectifier efficiency. The tunneling current of the rectifier is calculated using the transfer matrix method (TMM) and the nonequilibrium Green's function (NEGF). The figures of merit of the rectifier are analyzed, and the effect of the metals and insulator choices on these merits is investigated. A detailed parametric study of the coupled strips plasmonic transmission lines is presented and thoroughly discussed. The overall efficiencies of the proposed travelling wave rectennas ...

  9. An Effective Power Management Circuit system for Energy Harvesting Applications

    Directory of Open Access Journals (Sweden)

    Chun-Chang Wu

    2014-05-01

    Full Text Available A high-efficiency power management circuit is realized using TSMC 0.35μm CMOS process to convert energy harvested from the environment for battery storage as a suitable power supply for application circuitry. A high conversion efficiency (74% switching voltage regulator is designed to serve as a digital control circuit with greater tolerance to power noise. For noise-sensitive analog circuits such as amplifiers and the analog-to-digital converters, a linear low dropout (LDO regulator is also designed to provide a cleaner and more stable power supply. In addition, a microcontroller which can effectively control the power switching of each circuit block is also implemented. To prevent power waste, the system blocks normally stay in standby mode with extremely low power consumption. Each block will be turned on only when instructed to activate.

  10. Electrical characterization of a buckling thermal energy harvester

    Science.gov (United States)

    Trioux, E.; Rufer, L.; Monfray, S.; Skotnicki, T.; Muralt, P.; Basrour, S.

    2015-12-01

    This paper presents the electrical characterizations of a novel concept for thermal energy harvesting at micro scale. The devices presented here are based on a two-step transduction combining thermo-mechanical and piezoelectric conversion. The piezoelectric layer is directly integrated into a buckling bilayer plate made of aluminium and aluminium nitride. For the first time, we have characterized the structures electrically and we have investigated their output power during the buckling. Firstly, we have used an insulating tip to make the plate buckle in order to have an estimation of the output power due to piezoelectric contribution only, and to eliminate any pyroelectric contribution that might be present during the thermal actuation. Then, we heated up the structure and we collected the output signal with an instrumentation amplifier in order to measure the voltage generated during the buckling. The output power during the mechanical and the thermal buckling is compared in the paper.

  11. Auxetic piezoelectric energy harvesters for increased electric power output

    Science.gov (United States)

    Li, Qiang; Kuang, Yang; Zhu, Meiling

    2017-01-01

    This letter presents a piezoelectric bimorph with auxetic (negative Poisson's ratio) behaviors for increased power output in vibration energy harvesting. The piezoelectric bimorph comprises a 2D auxetic substrate sandwiched between two piezoelectric layers. The auxetic substrate is capable of introducing auxetic behaviors and thus increasing the transverse stress in the piezoelectric layers when the bimorph is subjected to a longitudinal stretching load. As a result, both 31- and 32-modes are simultaneously exploited to generate electric power, leading to an increased power output. The increasing power output principle was theoretically analyzed and verified by finite element (FE) modelling. The FE modelling results showed that the auxetic substrate can increase the transverse stress of a bimorph by 16.7 times. The average power generated by the auxetic bimorph is 2.76 times of that generated by a conventional bimorph.

  12. PZT thin films for piezoelectric MEMS mechanical energy harvesting

    Science.gov (United States)

    Yeager, Charles

    This thesis describes the optimization of piezoelectric Pb(ZrxTi 1-x)O3 (PZT) thin films for energy generation by mechanical energy harvesting, and self-powered micro-electro-mechanical systems (MEMS). For this purpose, optimization of the material was studied, as was the incorporation of piezoelectric films into low frequency mechanical harvesters. A systematic analysis of the energy harvesting figure of merit was made. As a figure of merit (e31,ƒ)2/epsilon r (transverse piezoelectric coefficient squared over relative permittivity) was utilized. PZT films of several tetragonal compositions were grown on CaF2, MgO, SrTiO3, and Si substrates, thereby separating the dependence of composition on domain orientation. To minimize artifacts associated with composition gradients, and to extend the temperature growth window, PZT films were grown by metal organic chemical vapor deposition (MOCVD). Using this method, epitaxial {001} films achieved c-domain textures above 90% on single crystal MgO and CaF2 substrates. This could be tailored via the thermal stresses established by the differences in thermal expansion coefficients of the film and the substrate. The single-domain e31,ƒ for PZT thin films was determined to exceed -12 C/m2 in the tetragonal phase field for x ≥ 0.19, nearly twice the phenomenologically modeled value. The utilization of c-domain PZT films is motivated by a figure of merit above 0.8 C2/m4 for (001) PZT thin films. Increases to the FoM via doping and hot poling were also quantified; a 1% Mn doping reduced epsilonr by 20% without decreasing the piezoelectric coefficient. Hot poling a device for one hour above 120°C also resulted in a 20% reduction in epsilonr ; furthermore, 1% Mn doping reduced epsilonr by another 12% upon hot poling. Two methods for fabricating thin film mechanical energy harvesting devices were investigated. It was found that phosphoric acid solutions could be used to pattern MgO crystals, but this was typically accompanied by

  13. Energy Harvesting from the Stray Electromagnetic Field around the Electrical Power Cable for Smart Grid Applications.

    Science.gov (United States)

    Khan, Farid Ullah

    2016-01-01

    For wireless sensor node (WSN) applications, this paper presents the harvesting of energy from the stray electromagnetic field around an electrical power line. Inductive and capacitive types of electrodynamic energy harvesters are developed and reported. For the produced energy harvesters, solid core and split-core designs are adopted. The inductive energy harvester comprises a copper wound coil which is produced on a mild steel core. However, the capacitive prototypes comprise parallel, annular discs separated by Teflon spacers. Moreover, for the inductive energy harvesters' wound coil and core, the parametric analysis is also performed. A Teflon housing is incorporated to protect the energy harvester prototypes from the harsh environmental conditions. Among the inductive energy harvesters, prototype-5 has performed better than the other harvesters and produces a maximum rms voltage of 908 mV at the current level of 155 A in the power line. However, at the same current flow, the capacitive energy harvesters produce a maximum rms voltage of 180 mV. The alternating output of the prototype-5 is rectified, and a super capacitor (1 F, 5.5 V) and rechargeable battery (Nickel-Cadmium, 3.8 V) are charged with it. Moreover, with the utilization of a prototype-5, a self-powered wireless temperature sensing and monitoring system for an electrical transformer is also developed and successfully implemented.

  14. Design and Fabrication of 3D Electrostatic Energy Harvester

    Directory of Open Access Journals (Sweden)

    V. Janicek

    2012-04-01

    Full Text Available This paper discusses the design of an electrostatic generator, power supply component of the self-powered microsystem, which is able to provide enough energy to power smart sensor chains or if necessary also other electronic monitoring devices. One of the requirements for this analyzer is the mobility, so designing the power supply expects use of an alternative way of getting electricity to power the device, rather than rely on periodic supply of external energy in the form of charging batteries, etc. In this case the most suitable method to use is so-called energy harvesting – a way how to gather energy. This uses the principle of non-electric conversion of energy into electrical energy in the form of converters. The present study describes the topology design of such structures of electrostatic generator. Structure is designed and modeled as a three-dimensional silicon based MEMS. Innovative approach involving the achievement of very low resonant frequency of the structure, while the minimum area of the chip, the ability to work in all 3 axes of coordinate system and ability to be tuned to reach desired parameters proves promising directions of possible further development of this issue. The work includes simulation of electro-mechanical and electrical properties of the structure, description of its behavior in different operating modes and phases of activity. Simulation results were compared with measured values of the produced prototype chip. These results can suggest possible modifications to the proposed structure for further optimization and application environment adaptation.

  15. EFRC: Polymer-Based Materials for Harvesting Solar Energy (stimulus)"

    Energy Technology Data Exchange (ETDEWEB)

    Russell, Thomas P. [Univ. of Massachusetts, Amherst, MA (United States)

    2016-12-08

    The University of Massachusetts Amherst is proposing an Energy Frontier Research Center (EFRC) on Polymer-Based Materials for Harvesting Solar Energy that will integrate the widely complementary experimental and theoretical expertise of 23 faculty at UMass-Amherst Departments with researchers from the University of Massachusetts Lowell, University of Pittsburgh, the Pennsylvania State University and Konarka Technologies, Inc. Collaborative efforts with researchers at the Oak Ridge National Laboratory, the University of Bayreuth, Seoul National University and Tohoku University will complement and expand the experimental efforts in the EFRC. Our primary research aim of this EFRC is the development of hybrid polymer-based devices with efficiencies more than twice the current organic-based devices, by combining expertise in the design and synthesis of photoactive polymers, the control and guidance of polymer-based assemblies, leadership in nanostructured polymeric materials, and the theory and modeling of non-equilibrium structures. A primary goal of this EFRC is to improve the collection and conversion efficiency of a broader spectral range of solar energy using the directed self-assembly of polymer-based materials so as to optimize the design and fabrication of inexpensive devices.

  16. 20000G shock energy harvesters for gun-fired munition

    Science.gov (United States)

    Willemin, J.; Boisseau, S.; Olmos, L.; Gallardo, M.; Despesse, G.; Robert, T.

    2016-11-01

    This paper presents a 20000G shock energy harvester dedicated to gun-fired munitions and based on a mass-spring resonant structure coupled to a coil-magnet electromagnetic converter. The 20000G shock energy is firstly stored in the spring as elastic potential energy, released as mass-spring mechanical oscillations right after the shock and finally converted into electricity thanks to the coil-magnet transducer. The device has been modeled, sized to generate 200mJ in 150ms, manufactured and tested in a gun-fired munition. The prototype sizes 117cm3 and weighs 370g. 210mJ have been generated in a test bench and 140mJ in real conditions; this corresponds to a mean output power of 0.93W (7.9mW/cm3) and a maximum output power of 4.83W (41.3mW/cm3) right after the shock.

  17. Photoactive supercapacitors for solar energy harvesting and storage

    Science.gov (United States)

    Takshi, Arash; Yaghoubi, Houman; Tevi, Tete; Bakhshi, Sara

    2015-02-01

    In most applications an energy storage device is required when solar cells are applied for energy harvesting. In this work, we have demonstrated that composite films of a conducting polymer and a dye can be used as photoactive electrodes in an electrochemical cell for concurrent solar energy conversion and charge storage. A device was made of poly ethylenedioxythiophene:polystyrene sulfonate and (PEDOT:PSS) and a porphyrin dye which showed a capacitance of ∼1.04 mF. The device was charged up to 430 mV (open circuit voltage) under a solar simulated illumination and was able to store the charge for more than 10 min in the dark. Further study on the concentration of the dye revealed the importance of the ratio between the dye and the conducting polymer to optimize the photovoltage and capacitance of the device. Also, the effect of the dye material was studied by using a Ruthenium (Ru) based dye. The device with the Ru dye showed a photovolatge of 198 mV and charge stability of more than 2 h.

  18. Analysis of thermal energy harvesting using ferromagnetic materials

    Energy Technology Data Exchange (ETDEWEB)

    Lallart, Mickaël, E-mail: mickael.lallart@insa-lyon.fr; Wang, Liuqing; Sebald, Gaël; Petit, Lionel; Guyomar, Daniel

    2014-09-05

    This Letter aims at giving a preliminary investigation of the thermal energy harvesting capabilities of a technique using the temperature-dependent permeability of ferromagnetic materials. The principles lie in the modification of the magnetic field caused by the variation of the permeability due to the temperature change, hence generating a voltage across a coil surrounding the circuit. The technique can be made truly passive by the use of magnets for applying bias magnetic field. Theoretical results, validated by experimental measurements, show a voltage output of 1.2 mV at optimal load of 2 Ω under 60 K temperature variation in 5 s (with a maximum slope of 25 K s{sup −1}). Further improvements, such as the use of low resistivity coil and magnet with high remnant magnetic field, indicate that it is possible to convert up to 7.35 μJ cm{sup −3} K{sup −2} cycle{sup −1}. - Highlights: • Ferromagnetic materials show a sharp change in their permeability near the Curie temperature. • A bias magnetic field permits changing the magnetic flux with the temperature. • The variable magnetic flux can be converted into electrical energy by using a coil. • Theoretical and experimental measurements show an energy density up to 7.35 μJ cm{sup −3} K{sup −2} cycle{sup −1}. • Optimization issues should focus on coil quality and global magnetic reluctance variation.

  19. Medium Access Control for Thermal Energy Harvesting in Advanced Metering Infrastructures

    DEFF Research Database (Denmark)

    Vithanage, Madava D.; Fafoutis, Xenofon; Andersen, Claus Bo

    2013-01-01

    In this paper we investigate the feasibility of powering wireless metering devices, namely heat cost allocators, by thermal energy harvested from radiators. The goal is to take a first step toward the realization of Energy-Harvesting Advanced Metering Infrastructures (EH-AMIs). While traditional...... battery-powered devices have a limited amount of energy, energy harvesting can potentially provide an infinite amount of energy for continuous operating lifetimes, thus reducing the cost involved in installation and maintenance. The contribution of this work is twofold. First, we experimentally identify...... the potential energy that can be harvested from Low Surface Temperature (LST) radiators. The experiments are based on a developed Energy-Harvesting Heat Cost Allocator (EH-HCA) prototype. On the basis of this measured power budget, we model and analytically compare the currently used Medium Access Control (MAC...

  20. Analytical solution and optimal design for galloping-based piezoelectric energy harvesters

    Science.gov (United States)

    Tan, T.; Yan, Z.

    2016-12-01

    The performance of the galloping-based piezoelectric energy harvester is usually investigated numerically. Instead of performing case studies by numerical simulations, analytical solutions of the nonlinear distributed parameter model are derived to capture the intrinsic effects of the physical parameters on the performance of such energy harvesters. The analytical solutions are confirmed with the numerical solutions. Optimal performance of such energy harvesters is therefore revealed theoretically. The electric damping due to the electromechanical coupling is defined. The design at the optimal electrical damping with smaller onset speed to galloping, higher harvested power, and acceptable tip displacement is superior than the design at the maximal electrical damping, as long as the optimal electrical damping can be achieved. Otherwise, the design at the maximal electrical damping should be then adopted. As the wind speed and aerodynamic empirical coefficients increase, the tip displacement and harvested power increase. This study provides a theoretical design and optimization procedure for galloping-based piezoelectric energy harvesters.

  1. Increased energy harvesting and reduced accelerative load for backpacks via frequency tuning

    Science.gov (United States)

    Xie, Longhan; Cai, Mingjing

    2015-06-01

    In this research, a backpack-based frequency-tuneable harvesting device was developed to harvest part of the human kinetic energy during walking and to relieve part of the accelerative load of the backpack from the bearer. The harvester employed a tuning mechanism to adjust the stretch ratio of the springs to adjust the system's stiffness so that the harvesting device can work in an appropriate status to generate more power and relieve a greater load from the bearer. The analysis indicates that adjusting the stiffness harvesting system to fit well with various external excitation conditions, can not only achieve more power output but also relieve part of the accelerative load from the bearer; and the experimental results agreed with the simulation. Compared with previous work, the harvester in this work had a higher efficiency in energy harvesting and could relieve an increased accelerative load from the bearer.

  2. Finite element analysis of hybrid energy harvesting of piezoelectric and electromagnetic

    Directory of Open Access Journals (Sweden)

    Muhammad Yazid Muhammad Ammar Faris

    2017-01-01

    Full Text Available Harvesting energy from ambient vibrations is a highly required method because of the wide range of available sources that produce vibration energy application from industrial machinery to human motion application. In this paper, the implementation of harvesting energy from two technologies to form a hybrid energy harvester system was analyzed. These two technologies involve the piezoelectric harvesting energy and the electromagnetic harvesting energy. A finite element model was developed using the Ansys software with the harmonic analysis solver to analyze and examine hybrid harvesting energy system. Both power output generated from the magnet and the piezoelectric is then combined to form one unit of energy. Further, it was found that the result shows the system generate the maximum power output of 14.85 μW from 100 Hz, 4.905 m/s2, and 0.6 cm3 for resonance frequency, acceleration, and the volume respectively from the optimal energy harvester design. Normalized Power Density (NPD result of 10.29 kgs/m3 comparable with other literature also can be used in energy harvesting system for vibration application.

  3. Exploring the roles of standard rectifying circuits on the performance of a nonlinear piezoelectric energy harvester

    Science.gov (United States)

    Tang, Lihua; Han, Yue; Hand, James; Harne, Ryan L.

    2016-04-01

    To enhance the energy conversion performance of piezoelectric vibration energy harvesters, such structures have been recently designed to leverage bandwidth-enhancing nonlinear dynamics. While key findings have been made, the majority of researchers have evaluated the opportunities when the harvesters are connected to pure resistive loads (AC interface). The alternating voltage generated by such energy harvesting systems cannot be directly utilized to power conventional electronics. Rectifying circuits are required to interface the device and electronic load but few efforts have considered how a standard rectifying DC interface circuit (DC interface) connected to a nonlinear piezoelectric energy harvester influences the system performance. The aim of this research is to begin exploring this critical feature of the nonlinear energy harvesting system. A nonlinear, monostable piezoelectric energy harvester (MPEH) is fabricated and evaluated to determine the generated power and useful operating bandwidth when connected to a DC interface. The nonlinearity is introduced into the harvester design by tuneable magnetic force. An equivalent circuit model of the MPEH is implemented with a user-defined nonlinear behavioral voltage source representative of the magnetic interaction. The model is validated comparing the open circuit voltage from circuit simulation and experiment. The practical energy harvesting capability of the MPEH connected to the AC and DC interface circuits are then investigated and compared, focusing on the influence of the varying load on the nonlinear dynamics and subsequent bandwidth and harvested power.

  4. Fluid-solid-electric lock-in of energy-harvesting piezoelectric flags

    CERN Document Server

    Xia, Yifan; Doare, Olivier

    2015-01-01

    The spontaneous flapping of a flag in a steady flow can be used to power an output circuit using piezoelectric elements positioned at its surface. Here, we study numerically the effect of inductive circuits on the dynamics of this fluid-solid-electric system and on its energy harvesting efficiency. In particular, a destabilization of the system is identified leading to energy harvesting at lower flow velocities. Also, a frequency lock-in between the flag and the circuit is shown to significantly enhance the system's harvesting efficiency. These results suggest promising efficiency enhancements of such flow energy harvesters through the output circuit optimization.

  5. Forest machine entrepreneurs in harvesting of energy wood; Metsaekoneyrittaejaet energiapuun korjuussa

    Energy Technology Data Exchange (ETDEWEB)

    Jaekaelae, M. [Koneyrittaejien liitto ry, Helsinki (Finland); Maekinen, P. [Finnish Forest Research Association, Vantaa (Finland)

    2000-07-01

    The amounts of energy wood harvested, and the effect on the turnover and the employment in the companies were studied. The effects of energy wood harvesting on the commercial timber harvesting, the factors affecting on the hardness of the work, as well as the machine technical problems have been studied. The forest entrepreneur's point of view has been taken into account in the research. The research is concentrated to the harvesting chains for logging residue chips. At present the logging residue chips are the most profitable part of the forest chips, so the predicted increase in the utilization will be concentrated to their recovery, at least in the first stage. Felling of the logging residues into stacks should support the production chains for logging residue chips, and in many cases also by a forest entrepreneur carrying out the forest haulage. The research was carried out as an interview of forest entrepreneurs active in harvesting of energy wood. 20 of these (25% of total) were interviewed. The entrepreneurs interviewed sold harvesting services to following purchasers: Biowatti Oy, Stora-Enso Oyj, UPM-Kymmene Oyj, Metsaeenergia ky and Kotimaiset energiat ky. Harvesting of energy wood had no effect on the rate of employment of the entrepreneurs. The entrepreneurs active in harvesting en ergy wood did not differ from other forest machine entrepreneurs. The amounts of energy wood, harvested by entrepreneurs have increased. The effects of harvesting energy wood on the activity of forest machine entrepreneurs will increase in the future. The questions concerning payment and technical solutions concerning harvesting will be highlighted. Forest machines, used for harvesting of commercial timber, can be used for harvesting logging residues. This requires changes in the normal working routines. Energy wood harvesting interferes with the harvesting of commercial timber. Processing of the stems more far away from the control room of a harvester was seen the main

  6. Energy harvesting from a multifrequency response of a tuned bending-torsion system

    Science.gov (United States)

    Abdelkefi, A.; Nayfeh, A. H.; Hajj, M. R.; Najar, F.

    2012-07-01

    We investigate the benefits of tuning the frequencies of an energy harvester to extract more energy from a base excitation that comprises three frequency components. The energy harvester is composed of a unimorph cantilever beam with asymmetric tip masses. By adjusting the asymmetry of the tip masses, we can tune this beam-mass structure to harvest energy from multifrequency components of a base excitation. We model the beam using the Euler-Bernoulli beam theory and use the first three global mode shapes of the harvester in a Galerkin procedure to derive a reduced-order model describing its response. We derive an exact analytical solution for the tip deflection, twisting angle, voltage output, and harvested electrical power. Using this solution, we investigate the advantages of harvesting energy from a response that contains multifrequencies in comparison to a response that contains a single frequency by tuning only the fundamental frequency. The advantages of this bending-torsion energy harvester and the effect of its tuning are investigated for different short- and open-circuit configurations. The results show that, through a proper tuning of this bending-torsion harvester, the harvested power can be increased significantly and it can be made to cover a wide range of electrical load resistances.

  7. Networks of triboelectric nanogenerators for harvesting water wave energy: a potential approach toward blue energy.

    Science.gov (United States)

    Chen, Jun; Yang, Jin; Li, Zhaoling; Fan, Xing; Zi, Yunlong; Jing, Qingshen; Guo, Hengyu; Wen, Zhen; Pradel, Ken C; Niu, Simiao; Wang, Zhong Lin

    2015-03-24

    With 70% of the earth's surface covered with water, wave energy is abundant and has the potential to be one of the most environmentally benign forms of electric energy. However, owing to lack of effective technology, water wave energy harvesting is almost unexplored as an energy source. Here, we report a network design made of triboelectric nanogenerators (TENGs) for large-scale harvesting of kinetic water energy. Relying on surface charging effect between the conventional polymers and very thin layer of metal as electrodes for each TENG, the TENG networks (TENG-NW) that naturally float on the water surface convert the slow, random, and high-force oscillatory wave energy into electricity. On the basis of the measured output of a single TENG, the TENG-NW is expected to give an average power output of 1.15 MW from 1 km(2) surface area. Given the compelling features, such as being lightweight, extremely cost-effective, environmentally friendly, easily implemented, and capable of floating on the water surface, the TENG-NW renders an innovative and effective approach toward large-scale blue energy harvesting from the ocean.

  8. Electrostatic MEMS vibration energy harvester for HVAC applications

    Science.gov (United States)

    Oxaal, J.; Hella, M.; Borca-Tasciuc, D.-A.

    2015-12-01

    This paper reports on an electrostatic MEMS vibration energy harvester with gapclosing interdigitated electrodes, designed for and tested on HVAC air ducts. The device is fabricated on SOI wafers using a custom microfabrication process. A dual-level physical stopper system is implemented in order to control the minimum gap between the electrodes and maximize the power output. It utilizes cantilever beams to absorb a portion of the impact energy as the electrodes approach the impact point, and a film of parylene with nanometer thickness deposited on the electrode sidewalls, which defines the absolute minimum gap and provides electrical insulation. The fabricated device was first tested on a vibration shaker to characterize its resonant behavior. The device exhibits spring hardening behavior due to impacts with the stoppers and spring softening behavior with increasing voltage bias. Testing was carried out on HVAC air duct vibrating with an RMS acceleration of 155 mgRMS and a primary frequency of 60 Hz with a PSD of 7.15·10-2 g2/Hz. The peak power measured is 12nW (0.6 nW RMS) with a PSD of 6.9·10-11 W/Hz at 240 Hz (four times of the primary frequency of 60 Hz), which is the highest output reported for similar vibration conditions and biasing voltages.

  9. Flutter-driven triboelectrification for harvesting wind energy.

    Science.gov (United States)

    Bae, Jihyun; Lee, Jeongsu; Kim, SeongMin; Ha, Jaewook; Lee, Byoung-Sun; Park, YoungJun; Choong, Chweelin; Kim, Jin-Baek; Wang, Zhong Lin; Kim, Ho-Young; Park, Jong-Jin; Chung, U-In

    2014-09-23

    Technologies to harvest electrical energy from wind have vast potentials because wind is one of the cleanest and most sustainable energy sources that nature provides. Here we propose a flutter-driven triboelectric generator that uses contact electrification caused by the self-sustained oscillation of flags. We study the coupled interaction between a fluttering flexible flag and a rigid plate. In doing so, we find three distinct contact modes: single, double and chaotic. The flutter-driven triboelectric generator having small dimensions of 7.5 × 5 cm at wind speed of 15 ms(-1) exhibits high-electrical performances: an instantaneous output voltage of 200 V and a current of 60 μA with a high frequency of 158 Hz, giving an average power density of approximately 0.86 mW. The flutter-driven triboelectric generation is a promising technology to drive electric devices in the outdoor environments in a sustainable manner.

  10. Energy harvesting to power sensing hardware onboard wind turbine blade

    Energy Technology Data Exchange (ETDEWEB)

    Carlson, Clinton P [Los Alamos National Laboratory; Schichting, Alexander D [Los Alamos National Laboratory; Quellette, Scott [Los Alamos National Laboratory; Farinholt, Kevin M [Los Alamos National Laboratory; Park, Gyuhae [Los Alamos National Laboratory

    2009-10-05

    Wind turbines are becoming a larger source of renewable energy in the United States. However, most of the designs are geared toward the weather conditions seen in Europe. Also, in the United States, manufacturers have been increasing the length of the turbine blades, often made of composite materials, to maximize power output. As a result of the more severe loading conditions in the United States and the material level flaws in composite structures, blade failure has been a more common occurrence in the U.S. than in Europe. Therefore, it is imperative that a structural health monitoring system be incorporated into the design of the wind turbines in order to monitor flaws before they lead to a catastrophic failure. Due to the rotation of the turbine and issues related to lightning strikes, the best way to implement a structural health monitoring system would be to use a network of wireless sensor nodes. In order to provide power to these sensor nodes, piezoelectric, thermoelectric and photovoltaic energy harvesting techniques are examined on a cross section of a CX-100 wind turbine blade in order to determine the feasibility of powering individual nodes that would compose the sensor network.

  11. CURRENT WAYS TO HARVEST ENERGY USING A COMPUTER MOUSE

    Directory of Open Access Journals (Sweden)

    Frantisek Horvat

    2014-02-01

    Full Text Available This paper deals with the idea of an energy harvesting (EH system that uses the mechanical energy from finger presses on the buttons of a computer mouse by means of a piezomaterial (PVF2. The piezomaterial is placed in the mouse at the interface between the button and the body. This paper reviews the parameters of the PVF2 piezomaterial and tests their possible implementation into EH systems utilizing these types of mechanical interactions. The paper tests the viability of two EH concepts: a battery management system, and a semi-autonomous system. A statistical estimate of the button operations is performed for various computer activities, showing that an average of up to 3300 mouse clicks per hour was produced for gaming applications, representing a tip frequency of 0.91 Hz on the PVF2 member. This frequency is tested on the PVF2 system, and an assessment of the two EH systems is reviewed. The results show that fully autonomous systems are not suitable for capturing low-frequency mechanical interactions, due to the parameters of current piezomaterials, and the resulting very long startup phase. However, a hybrid EH system which uses available power to initiate the circuit and eliminate the startup phase may be explored for future studies.

  12. Electrically conductive fabric based stretchable triboelectric energy harvester

    Science.gov (United States)

    Haque, Rubaiyet I.; Farine, Pierre-André; Briand, Danick

    2016-11-01

    Stretchable conductive fabric-based triboelectric generator (TENG), to develop breathing/chest band for harvesting energy at low frequency has been developed. Stretchable conductive nylon-fabric and carbon-based elastomer composites were used as electrodes. During this work, film casting technique was implemented and combination of different materials, such as, polydimethylsiloxane (PDMS) and polytetrafluoroethylene (PTFE)/ polyurethane (PU) were tested as triboelectric layers. The process was compatible with large scale fabrication. At low operation frequency of 1.0±0.1 Hz for the strain of 13±1.5%, developed TENGs provide output power densities of 0.06 μW/cm2 and 0.11 μW/cm2 for the load resistance of 100 MΩ, and energy density of 0.19±0.03 nJ/cm2/cycle and 0.08±0.01 nJ/cm2/cycle for the use of capacitor of 2.2 μF, for PDMS-PTFE and PDMS-PU based TENGs respectively.

  13. Impedance adaptation methods of the piezoelectric energy harvesting

    Science.gov (United States)

    Kim, Hyeoungwoo

    In this study, the important issues of energy recovery were addressed and a comprehensive investigation was performed on harvesting electrical power from an ambient mechanical vibration source. Also discussed are the impedance matching methods used to increase the efficiency of energy transfer from the environment to the application. Initially, the mechanical impedance matching method was investigated to increase mechanical energy transferred to the transducer from the environment. This was done by reducing the mechanical impedance such as damping factor and energy reflection ratio. The vibration source and the transducer were modeled by a two-degree-of-freedom dynamic system with mass, spring constant, and damper. The transmissibility employed to show how much mechanical energy that was transferred in this system was affected by the damping ratio and the stiffness of elastic materials. The mechanical impedance of the system was described by electrical system using analogy between the two systems in order to simply the total mechanical impedance. Secondly, the transduction rate of mechanical energy to electrical energy was improved by using a PZT material which has a high figure of merit and a high electromechanical coupling factor for electrical power generation, and a piezoelectric transducer which has a high transduction rate was designed and fabricated. The high g material (g33 = 40 [10-3Vm/N]) was developed to improve the figure of merit of the PZT ceramics. The cymbal composite transducer has been found as a promising structure for piezoelectric energy harvesting under high force at cyclic conditions (10--200 Hz), because it has almost 40 times higher effective strain coefficient than PZT ceramics. The endcap of cymbal also enhances the endurance of the ceramic to sustain ac load along with stress amplification. In addition, a macro fiber composite (MFC) was employed as a strain component because of its flexibility and the high electromechanical coupling

  14. Nanotechnologies for efficient solar and wind energy harvesting and storage

    Science.gov (United States)

    Eldada, Louay A.

    2010-08-01

    We describe nanotechnologies used to improve the efficient harvest of energy from the Sun and the wind, and the efficient storage of energy in secondary batteries and ultracapacitors, for use in a variety of applications including smart grids, electric vehicles, and portable electronics. We demonstrate high-quality nanostructured copper indium gallium selenide (CIGS) thin films for photovoltaic (PV) applications. The self-assembly of nanoscale p-n junction networks creates n-type networks that act as preferential electron pathways, and p-type networks that act as preferential hole pathways, allowing positive and negative charges to travel to the contacts in physically separated paths, reducing charge recombination. We also describe PV nanotechnologies used to enhance light trapping, photon absorption, charge generation, charge transport, and current collection. Furthermore, we describe nanotechnologies used to improve the efficiency of power-generating wind turbines. These technologies include nanoparticle-containing lubricants that reduce the friction generated from the rotation of the turbines, nanocoatings for de-icing and self-cleaning technologies, and advanced nanocomposites that provide lighter and stronger wind blades. Finally, we describe nanotechnologies used in advanced secondary batteries and ultracapacitors. Nanostructured powder-based and carbon-nanotube-based cathodes and anodes with ultra-high surface areas boost the energy and power densities in secondary batteries, including lithium-ion and sodium-sulfur batteries. Nanostructured carbon materials are also controlled on a molecular level to offer large surface areas for the electrodes of ultracapacitors, allowing to store and supply large bursts of energy needed in some applications.

  15. Analytical and experimental investigation of flexible longitudinal zigzag structures for enhanced multi-directional energy harvesting

    Science.gov (United States)

    Zhou, Shengxi; Hobeck, Jared D.; Cao, Junyi; Inman, Daniel J.

    2017-03-01

    This paper makes a complete investigation of flexible longitudinal zigzag (FLZ) energy harvesters for the purpose of enhancing energy harvesting from low-frequency and low-amplitude excitation. A general theoretical model of the FLZ energy harvesters with large joint block mass is proposed. In order to verify the accuracy of the theoretical model, both experimental results and finite element analysis via ANSYS software are presented. Results show that the theoretical model can successfully predict the dynamic response and the output power of the FLZ energy harvesters. Both theoretical and experimental results demonstrate that the proposed energy harvesters can effectively harvest vibration energy even when the direction of excitation relative to the harvester varies from 0° to 90°. Under the low excitation level of 0.18 m s‑2, the experimental maximum output power of a FLZ energy harvester with five beams was found to be 1.016 mW. Finally, the results indicate that the proposed structure is capable of effective energy conversion across a large range of excitation angles at low-frequency and low-amplitude excitations, which makes it suitable for a wide range of working conditions.

  16. Multiple Distributed Smart Microgrids with a Self-Autonomous, Energy Harvesting Wireless Sensor Network

    DEFF Research Database (Denmark)

    Guerrero, Josep M.; Kheng Tan, Yen

    2012-01-01

    The chapter covers the smart wireless sensors for microgrids, as well as the energy harvesting technology used to sustain the operations of these sensors. Last, a case study on the multiple distributed smart microgrids with a self-autonomous, energy harvesting wireless sensor network is presented....

  17. Electrostatic energy harvesting device with out-of-the-plane gap closing scheme

    DEFF Research Database (Denmark)

    Wang, Fei; Hansen, Ole

    2013-01-01

    In this paper, we report on an electrostatic energy harvester with an out-of-the-plane gap closing scheme. Using advanced MEMS technology, energy harvesting devices with a four wafer stack are batch fabricated and fully packaged at wafer scale. CYTOP polymer is used both as an electret material...

  18. Electrostatic energy harvesting device with out-of-the-plane gap closing scheme

    DEFF Research Database (Denmark)

    Wang, Fei; Hansen, Ole

    2014-01-01

    In this paper, we report on an electrostatic energy harvester with an out-of-the-plane gap closing scheme. Using advanced MEMS technology, energy harvesting devices formed by a four wafer stack are batch fabricated and fully packaged at wafer scale. A spin coated CYTOP polymer is used both...

  19. Energy Harvesting from the Stray Electromagnetic Field around the Electrical Power Cable for Smart Grid Applications

    Directory of Open Access Journals (Sweden)

    Farid Ullah Khan

    2016-01-01

    Full Text Available For wireless sensor node (WSN applications, this paper presents the harvesting of energy from the stray electromagnetic field around an electrical power line. Inductive and capacitive types of electrodynamic energy harvesters are developed and reported. For the produced energy harvesters, solid core and split-core designs are adopted. The inductive energy harvester comprises a copper wound coil which is produced on a mild steel core. However, the capacitive prototypes comprise parallel, annular discs separated by Teflon spacers. Moreover, for the inductive energy harvesters’ wound coil and core, the parametric analysis is also performed. A Teflon housing is incorporated to protect the energy harvester prototypes from the harsh environmental conditions. Among the inductive energy harvesters, prototype-5 has performed better than the other harvesters and produces a maximum rms voltage of 908 mV at the current level of 155 A in the power line. However, at the same current flow, the capacitive energy harvesters produce a maximum rms voltage of 180 mV. The alternating output of the prototype-5 is rectified, and a super capacitor (1 F, 5.5 V and rechargeable battery (Nickel-Cadmium, 3.8 V are charged with it. Moreover, with the utilization of a prototype-5, a self-powered wireless temperature sensing and monitoring system for an electrical transformer is also developed and successfully implemented.

  20. Vacuum-packaged piezoelectric vibration energy harvesters: Damping contributions and autonomy for a wireless sensor system

    NARCIS (Netherlands)

    Elfrink, R.; Renaud, M.; Kamel, T.M.; Nooijer, C. de; Jambunathan, M.; Goedbloed, M.; Hohlfeld, D.; Matova, S.; Pop, V.; Caballero, L.; Schaijk, R. van

    2010-01-01

    This paper describes the characterization of thin-film MEMS vibration energy harvesters based on aluminum nitride as piezoelectric material. A record output power of 85 μW is measured. The parasitic-damping and the energy-harvesting performances of unpackaged and packaged devices are investigated. V

  1. Acoustic Energy Harvesting Using Piezoelectric Generator for Low Frequency Sound Waves Energy Conversion

    Directory of Open Access Journals (Sweden)

    Haris Fazilah Hassan

    2014-01-01

    Full Text Available The applications of electronic devices with low power consumption, such as wireless sensor network and electronic communication devices, are rapidly increasing. Thus, utilizing environmental energy as an alternative to electrochemical battery, which has a finite lifespan, can be a great advantage to these electronic devices. Harvesting environmental energy, such as solar, thermal, wind flow, water current, and raindrops, has attracted increasing research interest in the field of energy harvesting. In this paper, harvesting sound energy in the form of pressure waves is investigated as an alternative to existing energy harvesting methods. In the experimental work, a piezoelectric generator lead zirconate titanate (PZT-5A cantilever type is used to extract sound energy from the loudspeaker from various distances and then to convert this energy into electrical energy. A direct piezoelectric effect operating in 31 coupling mode is used. The maximum voltage generated by the piezoelectric generator occurs when its resonant frequency is operating near the frequency of sound. An analytical method with an appropriate equation is used to determine the resonant frequency and is then validated using the experimental result. The result shows that the maximum output voltage of 26.7 mVrms was obtained with the sound intensity of 78.6 dB at resonant frequency of 62 Hz at 1 cm distance in the first mode. In the second mode, the maximum output voltage of 91 mVrms was obtained with the sound intensity of 102.6 dB at resonant frequency of 374 Hz at 1 cm distance which is larger than that of the first mode. However, for both modes, voltage decreases as distance increases.

  2. Scavenging energy from the motion of human lower limbs via a piezoelectric energy harvester

    Science.gov (United States)

    Fan, Kangqi; Yu, Bo; Zhu, Yingmin; Liu, Zhaohui; Wang, Liansong

    2017-03-01

    Scavenging energy from human motion through piezoelectric transduction has been considered as a feasible alternative to batteries for powering portable devices and realizing self-sustained devices. To date, most piezoelectric energy harvesters (PEHs) developed can only collect energy from the uni-directional mechanical vibration. This deficiency severely limits their applicability to human motion energy harvesting because the human motion involves diverse mechanical motions. In this paper, a novel PEH is proposed to harvest energy from the motion of human lower limbs. This PEH is composed of two piezoelectric cantilever beams, a sleeve and a ferromagnetic ball. The two beams are designed to sense the vibration along the tibial axis and conduct piezoelectric conversion. The ball senses the leg swing and actuates the two beams to vibrate via magnetic coupling. Theoretical and experimental studies indicate that the proposed PEH can scavenge energy from both the vibration and the swing. During each stride, the PEH can produce multiple peaks in voltage output, which is attributed to the superposition of different excitations. Moreover, the root-mean-square (RMS) voltage output of the PEH increases when the walking speed ranges from 2 to 8 km/h. In addition, the ultra-low frequencies of human motion are also up-converted by the proposed design.

  3. Investigation of folded spring structures for vibration-based piezoelectric energy harvesting

    Science.gov (United States)

    Lueke, J.; Rezaei, M.; Moussa, W. A.

    2014-12-01

    This paper presents a fixed-fixed folded spring as an alternative elastic element for beam-based piezoelectric energy harvesting. In order to harvest energy from low frequency vibration in an optimal manner, the natural/operational frequencies of harvesters must be reduced to match low frequency input vibrations. Therefore, natural frequency reduction of vibration-based energy harvesters is critical to maximize output power at low operational frequency. The mechanical optimization of cantilever-based piezoelectric energy harvesters is limited by residual stress-based beam curling that produced through microfabrication adding additional mechanical stiffness to the system. The fixed-fixed folded spring structure presented in this paper allows for increased effective beam length and residual stress relaxation, without out of plane beam curling to further reducing the natural frequency. Multiple designs of folded spring energy harvesters are presented to demonstrate the effect of important design parameters. It is shown that the folded spring harvesters were capable of harvesting electricity at low natural frequencies, ranging from 45 Hz to 3667 Hz. Additionally, the harvesters were shown to be insensitive to microfabrication-based residual stress beam curling. The maximum power output achieved by the folded spring harvesters was 690.5 nW at 226.3 Hz for a single harvesting element of an array, with a PZT layer thickness of 0.24 μm. The work presented in this paper demonstrates that the fixed-fixed folded spring can be used as a viable structural element for low frequency piezoelectric energy harvesting to take advantage of ambient vibrations found in low frequency applications.

  4. Regulating the Energy Flow in a Cyanobacterial Light-Harvesting Antenna Complex.

    Science.gov (United States)

    Eisenberg, Ido; Caycedo-Soler, Felipe; Harris, Dvir; Yochelis, Shira; Huelga, Susana F; Plenio, Martin B; Adir, Noam; Keren, Nir; Paltiel, Yossi

    2017-02-16

    Photosynthetic organisms harvest light energy, utilizing the absorption and energy-transfer properties of protein-bound chromophores. Controlling the harvesting efficiency is critical for the optimal function of the photosynthetic apparatus. Here, we show that the cyanobacterial light-harvesting antenna complex may be able to regulate the flow of energy to switch reversibly from efficient energy conversion to photoprotective quenching via a structural change. We isolated cyanobacterial light-harvesting proteins, phycocyanin and allophycocyanin, and measured their optical properties in solution and in an aggregated-desiccated state. The results indicate that energy band structures are changed, generating a switch between the two modes of operation, exciton transfer and quenching, achieved without dedicated carotenoid quenchers. This flexibility can contribute greatly to the large dynamic range of cyanobacterial light-harvesting systems.

  5. Design of piezoelectric energy harvesting devices subjected to broadband random vibrations by applying topology optimization

    Institute of Scientific and Technical Information of China (English)

    Zhe-Qi Lin; Hae Chang Gea; Shu-Tian Liu

    2011-01-01

    Converting ambient vibration energy into electrical energy by using piezoelectric energy harvester has attracted a lot of interest in the past few years.In this paper,a topology optimization based method is applied to simultaneously determine the optimal layout of the piezoelectric energy harvesting devices and the optimal position of the mass loading.The objective function is to maximize the energy harvesting performance over a range of vibration frequencies.Pseudo excitation method (PEM) is adopted to analyze structural stationary random responses,and sensitivity analysis is then performed by using the adjoint method.Numerical examples are presented to demonstrate the validity of the proposed approach.

  6. Power/Energy Estimator for Designing WSN Nodes with Ambient Energy Harvesting Feature

    Directory of Open Access Journals (Sweden)

    Jutel Dominique

    2011-01-01

    Full Text Available Abstract Wireless Sensor Networks (WSNs consist of spatially distributed autonomous sensors to cooperatively monitor physical conditions. Thus, the node battery autonomy is critical. To outperform it, most WSNs rely on the harvesting capability. As nodes can recharge whenever energy is available, the problem is to determine at design time the node autonomy. For our project, we solve it by creating a power/energy estimator that simulates business scenarios to predict node autonomy; the estimation concerns both power and energy features. Based on node architecture configuration, its Dynamic Power Management (DPM policy, and environmental conditions, we present a simulator that helps identify power consumption hot spots and make critical choices during the system design. It also helps to scale the energy storage system as well as the energy harvesters correctly. The hardware part is modelled using the FLPA methodology to develop different node component models with a variable accuracy. For the logical part, we developped a specific DPM by integrating meteorology and weather forecast behaviours. The novelty comes from the ability to simulate the WSN harvesting capability and to estimate at runtime the remaining duration of each service.

  7. Energy and industrial wood harvesting from young forests; Energia- ja ainespuun korjuu nuorista metsistae

    Energy Technology Data Exchange (ETDEWEB)

    Rieppo, K.; Mutikainen, A.; Jouhiaho, A. (eds.)

    2011-07-01

    In the METKA Forest Energy Profitably project TTS (Work Efficiency Institute) compared methods suitable for the harvesting of energy wood and industrial wood. During the thinning of a young forest by a forest worker, the whole-tree logging method was one-third less expensive than the pulpwood method, including terrain transport. In harvesting whole trees as part of the thinning of young forests, methods based on combinations of manual and mechanized workproved to be several dozen per cent less expensive than the entirely mechanized method. When cutting energy wood with a Harveri small harwarder productivity was slightly higher when using 40-metre distances two cutting trails than when using 20-metre distances. When using a Tehojaetkae small harvester, creating two cutting trails in addition to the standard four-metre-wide cutting trail resulted in slightly higher productivity than creating three narrow cutting trails. A Risutec L3A energy head was used in tests involving both clearing and energy wood cutting. This method proved to be very promising, and it seems highly proable that advance clearing will no longer be needed in energy wood harvesting under all circumstances. When using traditional harvester-forwarder chains and a harvarder for first thinning in pine stands, the harvesting of entirely or partly non-delimbed trees was 20 to 40 per cent less expensive per harvested cubic meter than the harvesting of delimbed trees. In tests carried out using the Naarva RS25 harvester head for first thinning in pine stands, the integrated method resulted in approximately one-third productivity than the traditional cutting of industrial wood. In a spruce-dominant site with delayed first thinning, the unit costs of harvesting delimbed energy wood were 16 per cent lower than those of the harvesting of pulpwood. In the future development of machinery, it will be important to aim at continuous motion, at least in terms of cutting small trees. (orig.)

  8. Piezoelectric Energy Harvesting Devices: An Alternative Energy Source for Wireless Sensors

    Directory of Open Access Journals (Sweden)

    Action Nechibvute

    2012-01-01

    Full Text Available The recent advances in ultralow power device integration, communication electronics, and microelectromechanical systems (MEMS technology have fuelled the emerging technology of wireless sensor networks (WSNs. The spatial distributed nature of WSNs often requires that batteries power the individual sensor nodes. One of the major limitations on performance and lifetime of WSNs is the limited capacity of these finite power sources, which must be manually replaced when they are depleted. Moreover, the embedded nature of some of the sensors and hazardous sensing environment make battery replacement very difficult and costly. The process of harnessing and converting ambient energy sources into usable electrical energy is called energy harvesting. Energy harvesting raises the possibility of self-powered systems which are ubiquitous and truly autonomous, and without human intervention for energy replenishment. Among the ambient energy sources such as solar energy, heat, and wind, mechanical vibrations are an attractive ambient source mainly because they are widely available and are ideal for the use of piezoelectric materials, which have the ability to convert mechanical strain energy into electrical energy. This paper presents a concise review of piezoelectric microgenerators and nanogenerators as a renewable energy resource to power wireless sensors.

  9. Multi-link piezoelectric structure for vibration energy harvesting

    Science.gov (United States)

    Aryanpur, Rameen M.; White, Robert D.

    2012-04-01

    Work in piezoelectric vibration energy harvesting has typically focused on single member cantilevered structures with transverse tip displacement at a known frequency, taking advantage of the optimal coupling characteristics of piezoceramics in the 3-1 bending mode. Multi-member designs could be advantageous in delivering power to a load in environments with random or wide-band vibrations. The design presented in this work consists of two hinged piezoceramic (PZT-5A) beams x-poled for series operation. Each beam measures 31.8mm x 12.7mm x 0.38mm and consists of two layers of nickel-plated piezoceramic adhered to a brass center shim. The hinge device consists of two custom-machined aluminum attachments epoxied to the end of a beam and connected using a 1.59mm diameter alloy steel dowel. A stainless steel torsion spring is placed over the pin and attached to the aluminum body to provide a restoring torque when under rotation. The design is modeled using the piezoelectric constitutive equations to solve for voltage and power for a set of electromechanical boundary conditions. Experimental measurements on the design are achieved by bolting one end of the structure to a vibration shaker and fixing the other to a rigid framework of industrial aluminum framing material. For a given frequency of vibration, power output of the structure can be obtained by measuring voltage drop across a resistive load.

  10. Energy harvesting from hydroelectric systems for remote sensors

    Directory of Open Access Journals (Sweden)

    Joaquim Azevedo

    2016-10-01

    Full Text Available Hydroelectric systems are well-known for large scale power generation. However, there are virtually no studies on energy harvesting with these systems to produce tens or hundreds of milliwatts. The goal of this work was to study which design parameters from large-scale systems can be applied to small-scale systems. Two types of hydro turbines were evaluated. The first one was a Pelton turbine which is suitable for high heads and low flow rates. The second one was a propeller turbine used for low heads and high flow rates. Several turbine geometries and nozzle diameters were tested for the Pelton system. For the propeller, a three-bladed turbine was tested for different heads and draft tubes. The mechanical power provided by these turbines was measured to evaluate the range of efficiencies of these systems. A small three-phase generator was developed for coupling with the turbines in order to evaluate the generated electric power. Selected turbines were used to test battery charging with hydroelectric systems and a comparison between several efficiencies of the systems was made.

  11. A 3D printed electromagnetic nonlinear vibration energy harvester

    Science.gov (United States)

    Constantinou, P.; Roy, S.

    2016-09-01

    A 3D printed electromagnetic vibration energy harvester is presented. The motion of the device is in-plane with the excitation vibrations, and this is enabled through the exploitation of a leaf isosceles trapezoidal flexural pivot topology. This topology is ideally suited for systems requiring restricted out-of-plane motion and benefits from being fabricated monolithically. This is achieved by 3D printing the topology with materials having a low flexural modulus. The presented system has a nonlinear softening spring response, as a result of designed magnetic force interactions. A discussion of fatigue performance is presented and it is suggested that whilst fabricating, the raster of the suspension element is printed perpendicular to the flexural direction and that the experienced stress is as low as possible during operation, to ensure longevity. A demonstrated power of ˜25 μW at 0.1 g is achieved and 2.9 mW is demonstrated at 1 g. The corresponding bandwidths reach up-to 4.5 Hz. The system’s corresponding power density of ˜0.48 mW cm-3 and normalised power integral density of 11.9 kg m-3 (at 1 g) are comparable to other in-plane systems found in the literature.

  12. Thin Thermoelectric Generator System for Body Energy Harvesting

    Science.gov (United States)

    Settaluri, Krishna T.; Lo, Hsinyi; Ram, Rajeev J.

    2012-06-01

    Wearable thermoelectric generators (TEGs) harvest thermal energy generated by the body to generate useful electricity. The performance of these systems is limited by (1) the small working temperature differential between the body and ambient, (2) the desire to use natural air convection cooling on the cold side of the generator, and (3) the requirement for thin, lightweight systems that are comfortable for long-term use. Our work has focused on the design of the heat transfer system as part of the overall thermoelectric (TE) system. In particular, the small heat transfer coefficient for natural air convection results in a module thermal impedance that is smaller than that of the heat sink. In this heat-sink-limited regime, the thermal resistance of the generator should be optimized to match that of the heat sink to achieve the best performance. In addition, we have designed flat (1 mm thickness) copper heat spreaders to realize performance surpassing splayed pin heat sinks. Two-dimensional (2-D) heat spreading exploits the large surface area available in a wristband and allows patterned copper to efficiently cool the TE. A direct current (DC)/DC converter is integrated on the wristband. The system generates up to 28.5 μW/cm2 before the converter and 8.6 μW/cm2 after the converter, with 30% efficiency. It generates output of 4.15 V with overall thickness under 5 mm.

  13. Improving Pyroelectric Energy Harvesting Using a Sandblast Etching Technique

    Directory of Open Access Journals (Sweden)

    An-Shen Siao

    2013-09-01

    Full Text Available Large amounts of low-grade heat are emitted by various industries and exhausted into the environment. This heat energy can be used as a free source for pyroelectric power generation. A three-dimensional pattern helps to improve the temperature variation rates in pyroelectric elements by means of lateral temperature gradients induced on the sidewalls of the responsive elements. A novel method using sandblast etching is successfully applied in fabricating the complex pattern of a vortex-like electrode. Both experiment and simulation show that the proposed design of the vortex-like electrode improved the electrical output of the pyroelectric cells and enhanced the efficiency of pyroelectric harvesting converters. A three-dimensional finite element model is generated by commercial software for solving the transient temperature fields and exploring the temperature variation rate in the PZT pyroelectric cells with various designs. The vortex-like type has a larger temperature variation rate than the fully covered type, by about 53.9%.The measured electrical output of the vortex-like electrode exhibits an obvious increase in the generated charge and the measured current, as compared to the fully covered electrode, by of about 47.1% and 53.1%, respectively.

  14. Single crystal PMN-PT/epoxy 1-3 composite for energy-harvesting application.

    Science.gov (United States)

    Ren, Kailiang; Liu, Yiming; Geng, Xuecang; Hofmann, Heath F; Zhang, Qiming M

    2006-03-01

    One key parameter in using electroactive materials to harvest electric energy from mechanical sources is the energy conversion efficiency. Recently, it was shown that, in the relaxor ferroelectric PMN-PT single crystals, a very high longitudinal electromechanical coupling factor (>90%) can be obtained. This paper investigates energy harvesting using 1-3 composites of PMN-PT single crystals in a soft epoxy matrix. It is shown that 1-3 composites enable the single crystals operating in the longitudinal mode to achieve high efficiency for energy harvesting, and the soft-polymer, matrix-supported single-crystal rods maintain high mechanical integrity under different external loads. For comparison, 1-3 composites with piezoceramic PZT also are investigated in energy-harvesting applications, and the results show that the high coupling factor of single crystal PMN-PT 1-3 composites leads to much higher electric energy output for similar mechanical energy input. The harvested energy density of 1-3 composite with single crystal (22.1 mW/cm3 under a stress of 40.4 MPa) is about twice of that harvested with PZT ceramic 1-3 composite (12 mW/cm3 under a stress of 39 MPa). At a higher stress level, the harvested-energy density of 1-3 PMN-PT single crystal composite can reach 96 mW/cm3.

  15. Effectiveness Testing of a Piezoelectric Energy Harvester for an Automobile Wheel Using Stochastic Resonance.

    Science.gov (United States)

    Zhang, Yunshun; Zheng, Rencheng; Shimono, Keisuke; Kaizuka, Tsutomu; Nakano, Kimihiko

    2016-10-17

    The collection of clean power from ambient vibrations is considered a promising method for energy harvesting. For the case of wheel rotation, the present study investigates the effectiveness of a piezoelectric energy harvester, with the application of stochastic resonance to optimize the efficiency of energy harvesting. It is hypothesized that when the wheel rotates at variable speeds, the energy harvester is subjected to on-road noise as ambient excitations and a tangentially acting gravity force as a periodic modulation force, which can stimulate stochastic resonance. The energy harvester was miniaturized with a bistable cantilever structure, and the on-road noise was measured for the implementation of a vibrator in an experimental setting. A validation experiment revealed that the harvesting system was optimized to capture power that was approximately 12 times that captured under only on-road noise excitation and 50 times that captured under only the periodic gravity force. Moreover, the investigation of up-sweep excitations with increasing rotational frequency confirmed that stochastic resonance is effective in optimizing the performance of the energy harvester, with a certain bandwidth of vehicle speeds. An actual-vehicle experiment validates that the prototype harvester using stochastic resonance is capable of improving power generation performance for practical tire application.

  16. Energy harvesting using parametric resonant system due to time-varying damping

    Science.gov (United States)

    Scapolan, Matteo; Tehrani, Maryam Ghandchi; Bonisoli, Elvio

    2016-10-01

    In this paper, the problem of energy harvesting is considered using an electromechanical oscillator. The energy harvester is modelled as a spring-mass-damper, in which the dissipated energy in the damper can be stored rather than wasted. Previous research provided the optimum damping parameter, to harvest maximum amount of energy, taking into account the stroke limit of the device. However, the amount of the maximum harvested energy is limited to a single frequency in which the device is tuned. Active and semi-active strategies have been suggested, which increases the performance of the harvester. Recently, nonlinear damping in the form of cubic damping has been proposed to extend the dynamic range of the harvester. In this paper, a periodic time-varying damper is introduced, which results in a parametrically excited system. When the frequency of the periodic time-varying damper is twice the excitation frequency, the system internal energy increases proportionally to the energy already stored in the system. Thus, for certain parametric damping values, the system can become unstable. This phenomenon can be exploited for energy harvesting. The transition curves, which separate the stable and unstable dynamics are derived, both analytically using harmonic balance method, and numerically using time simulations. The design of the harvester is such that its response is close to the transition curves of the Floquet diagram, leading to stable but resonant system. The performance of the parametric harvester is compared with the non-parametric one. It is demonstrated that performances and the frequency bandwidth in which the energy can be harvested can be both increased using time-varying damping.

  17. Energy Autonomous Wireless Water Meter with Integrated Turbine Driven Energy Harvester

    Science.gov (United States)

    Becker, P.; Folkmer, B.; Goepfert, R.; Hoffmann, D.; Willmann, A.; Manoli, Y.

    2013-12-01

    Accurate meter reading is the fundamental task of the home water system for the handling of payments. Meters need to be read correctly, to avoid an effect of adding events that increase unnecessary cost and create customer dissatisfaction. This paper presents a fully integrated wireless, energy autonomous water metering system based on the European Standard EN 13757 "Communication systems for meters and remote reading of meters". The system can be used in multiple water metering scenarios. No maintenance will be required and the system will provide precise and secure data transmission as well as timely and accurate recording of the consumption of water. The identification of any leakages will be improved through the analysis of the actual quantity supplied and recorded by the meters. The system is powered by an energy harvester, based on a water driven turbine wheel that is directly coupled to an electromagnetic energy transducer. The power delivered by the generator is dependent of the amount of flowing water and the pressure in the water pipes. Therefor the power is commonly non-continuous, fluctuant and unstable in the voltage amplitude. To be able to report the meter readings at all times, the system needs to be powered not only in times when the energy harvester delivers energy. Therefor an energy buffer, that stores the harvested energy, is installed to compensate the energy requirement between the actual generator output and the energy consumption of the application. Besides a complete system overview, the presentation will focus on the power management and energy aware battery charging circuitry. The design, fabrication, measuring results and the preparations for field tests in rural and urban environment will be presented and discussed.

  18. Shock reliability analysis and improvement of MEMS electret-based vibration energy harvesters

    Science.gov (United States)

    Renaud, M.; Fujita, T.; Goedbloed, M.; de Nooijer, C.; van Schaijk, R.

    2015-10-01

    Vibration energy harvesters can serve as a replacement solution to batteries for powering tire pressure monitoring systems (TPMS). Autonomous wireless TPMS powered by microelectromechanical system (MEMS) electret-based vibration energy harvester have been demonstrated. The mechanical reliability of the MEMS harvester still has to be assessed in order to bring the harvester to the requirements of the consumer market. It should survive the mechanical shocks occurring in the tire environment. A testing procedure to quantify the shock resilience of harvesters is described in this article. Our first generation of harvesters has a shock resilience of 400 g, which is far from being sufficient for the targeted application. In order to improve this aspect, the first important aspect is to understand the failure mechanism. Failure is found to occur in the form of fracture of the device’s springs. It results from impacts between the anchors of the springs when the harvester undergoes a shock. The shock resilience of the harvesters can be improved by redirecting these impacts to nonvital parts of the device. With this philosophy in mind, we design three types of shock absorbing structures and test their effect on the shock resilience of our MEMS harvesters. The solution leading to the best results consists of rigid silicon stoppers covered by a layer of Parylene. The shock resilience of the harvesters is brought above 2500 g. Results in the same range are also obtained with flexible silicon bumpers, which are simpler to manufacture.

  19. On the efficiency of energy harvesting using vortex-induced vibrations of cables

    CERN Document Server

    Grouthier, Clement; Bourguet, Remi; Modarres-Sadeghi, Yahya; de Langre, Emmanuel

    2014-01-01

    Many technologies based on fluid-structure interaction mechanisms are being developed to harvest energy from geophysical flows. The velocity of such flows is low, and so is their energy density. Large systems are therefore required to extract a significant amount of energy. The question of the efficiency of energy harvesting using vortex-induced vibrations (VIV) of cables is addressed in this paper, through two reference configurations: (i) a long tensioned cable with periodically-distributed harvesters and (ii) a hanging cable with a single harvester at its upper extremity. After validation against either direct numerical simulations or experiments, an appropriate reduced-order wake- oscillator model is used to perform parametric studies of the impact of the harvesting parameters on the efficiency. For both configurations, an optimal set of parameters is identified and it is shown that the maximum efficiency is close to the value reached with an elastically-mounted rigid cylinder. The variability of the effi...

  20. Nonlinear interface between the piezoelectric harvesting structure and the modulating circuit of an energy harvester with a real storage battery.

    Science.gov (United States)

    Hu, Yuantai; Xue, Huan; Hu, Ting; Hu, Hongping

    2008-01-01

    This paper studies the performance of an energy harvester with a piezoelectric bimorph (PB) and a real electrochemical battery (ECB), both are connected as an integrated system through a rectified dc-dc converter (DDC). A vibrating PB can scavenge energy from the operating environment by the electromechanical coupling. A DDC can effectively match the optimal output voltage of the harvesting structure to the battery voltage. To raise the output power density of PB, a synchronized switch harvesting inductor (SSHI) is used in parallel with the harvesting structure to reverse the voltage through charge transfer between the output electrodes at the transition moments from closed-to open-circuit. Voltage reversal results in earlier arrival of rectifier conduction because the output voltage phases of any two adjacent closed-circuit states are just opposite each other. In principle, a PB is with a smaller, flexural stiffness under closed-circuit condition than under open-circuit condition. Thus, the PB subjected to longer closed-circuit condition will be easier to be accelerated. A larger flexural velocity makes the PB to deflect with larger amplitude, which implies that more mechanical energy will be converted into an electric one. Nonlinear interface between the vibrating PB and the modulating circuit is analyzed in detail, and the effects of SSHI and DDC on the charging efficiency of the storage battery are researched numerically. It was found that the introduction of a DDC in the modulating circuit and an SSHI in the harvesting structure can raise the charging efficiency by several times.

  1. Combining dissimilar materials at nanometer scale for energy harvesting

    Science.gov (United States)

    Kobayashi, Nobuhiko P.

    2010-04-01

    The development of next-generation energy resources that are reliable and economically/environmentally acceptable is a key to harnessing and providing the resources essential for the life of mankind. Our research focuses on the development of novel semiconductor platforms that would significantly benefit energy harvesting, in particular, from light and heat. In these critical applications, traditional semiconductor solid-state devices, such as photovoltaic (PV) and thermoelectric (TE) devices based on a stack of single-crystal semiconductor thin films or single-crystal bulk semiconductor have several drawbacks, for instance; scalability-limits arise when ultra-large-scale implementation is envisioned for PV devices and performance-limits arise for TE devices in which the interplay of both electronic and phonon systems is important. In our research, various types of nanometer-scale semiconductor structures (e.g., nanowires and nanoparticles) coupled to or embedded within a micrometer-scale semiconductor structure (i.e., semiconductor nanomicrometer hybrid platforms) are explored to build a variety of non-conventional PV and TE devices. Two core projects are to develop semiconductor nano-micrometer hybrid platforms based on (1) an ensemble of single-crystal semiconductor nanowires connected to non-single-crystal semiconductor surfaces and (2) semimetallic nanoparticles embedded within a single-crystal semiconductor. The semiconductor nano-micrometer hybrid platforms are studied within the context of their basic electronic, optical, and thermal properties, which will be further assessed and validated by comparison with theoretical approaches to draw comprehensive pictures of physicochemical properties of these semiconductor platforms.

  2. Light harvesting via energy transfer in the dye solar cell

    Energy Technology Data Exchange (ETDEWEB)

    Siegers, Conrad

    2007-11-09

    The PhD-thesis ''Light Harvesting via Energy Transfer in the Dye Solar Cell'' (University of Freiburg, July 2007) describes the conceptual design, synthesis and testing of energy donor acceptor sensitizers for the dye solar cell (DSC). Under monochromatic illumination solar cells sensitized with the novel donor acceptor systems revealed a higher power conversion efficiency than cells containing exclusively the acceptor component. The following approach led to this conclusion: (i) the choice of suitable chromophores as energy donor and acceptor moieties according to the Foerster-theory, (ii) the synthesis of different donor acceptor systems, (iii) the development of a methodology allowing the quantification of energy transfer within dye solar cells, and (iv) the evaluation of characteristics of DSCs that were sensitized with the different donor acceptor systems. The acceptor chromophores used in this work were derived from [Ru(dcbpy)2acac]Cl (dcbpy = 4,4'-dicarboxy-2,2'-bipyridin, acac = acetylacetonato). This complex offered the opportunity to introduce substituents at the acac-ligand's terminal CH3 groups without significantly affecting its excellent photoelectrochemical properties. Alkylated 4-amino-1,8-naphthalimides (termed Fluorols in the following) were used as energy donor chromophores. This class of compounds fulfils the requirements for efficient energy transfer to [Ru(dcbpy)2acac]Cl. Covalently linking donor and acceptor chromophores to one another was achieved by two different concepts. A dyad comprising one donor and one acceptor chromophore was synthesized by subsequent hydrosilylation steps of an olefin-bearing donor and an acceptor precursor to the dihydrosilane HSiMe2-CH2CH2-SiMe2H. A series of polymers comprising multiple donor and acceptor units was made by the addition of alkyne-bearing chromophores to hyperbranched polyglycerol azide (''Click-chemistry''). In this series the donor acceptor

  3. Capacity of Fading Gaussian Channel with an Energy Harvesting Sensor Node

    CERN Document Server

    Rajesh, R

    2010-01-01

    Network life time maximization is becoming an important design goal in wireless sensor networks. Energy harvesting has recently become a preferred choice for achieving this goal as it provides near perpetual operation. We study such a sensor node with an energy harvesting source and compare various architectures by which the harvested energy is used. We find its Shannon capacity when it is transmitting its observations over a fading AWGN channel with perfect/no channel state information provided at the transmitter. We also obtain the capacity with a finite energy buffer via Markov decision theory.

  4. Theoretical and applied research on bistable dual-piezoelectric-cantilever vibration energy harvesting toward realistic ambience

    Science.gov (United States)

    Gao, Y.; Leng, Y.; Javey, A.; Tan, D.; Liu, J.; Fan, S.; Lai, Z.

    2016-11-01

    Pink noise, which is similar to realistic ambient noise, is normally used to simulate ambience where a piezoelectric energy harvesting system (PEHS) is set up. However, pink noise with standard spectral representation can only be used to simulate excitations assumed to possess constant intensity, whereas realistic ambient noise normally appears with a random spectrum and varying intensity in terms of different locations and time. The output performance of conventional bistable magnetic repulsive energy harvesters is significantly affected by the ambience intensity. Considering this fact, a model bistable dual-piezoelectric-cantilever energy harvester (DPEH) is developed in this study to achieve optimal broadband energy harvesting under a varying-intensity realistic circumstance. We utilized various realistic ambient conditions as excitations to obtain the DPEH energy harvesting performance for theoretical and applied study. The elastically supported PEHS has been proven to be more adaptive to realistic ambience with significant or medium intensity variation, but is less qualified for realistic ambience with constant intensity compared with the rigidly supported PEHS (RPEHS). Fortunately, the dual-piezoelectric-cantilever energy harvesting system is superior to the RPEHS under all circumstances because the dual-piezoelectric cantilevers are efficiently utilized for electromechanical energy conversion to realize optimal energy harvesting.

  5. Smart nanocoated structure for energy harvesting at low frequency vibration

    Science.gov (United States)

    Sharma, Sudhanshu

    Increasing demands of energy which is cleaner and has an unlimited supply has led development in the field of energy harvesting. Piezoelectric materials can be used as a means of transforming ambient vibrations into electrical energy that can be stored and used to power other devices. With the recent surge of micro scale devices, piezoelectric power generation can provide a convenient alternative to traditional power sources. In this research, a piezoelectric power generator composite prototype was developed to maximize the power output of the system. A lead zirconate titanate (PZT) composite structure was formed and mounted on a cantilever bar and was studied to convert vibration energy of the low range vibrations at 30 Hz--1000 Hz. To improve the performance of the PZT, different coatings were made using different percentage of Ferrofluid (FNP) and Zinc Oxide nanoparticles (ZnO) and binder resin. The optimal coating mixture constituent percentage was based on the performance of the composite structure formed by applying the coating on the PZT. The fabricated PZT power generator composite with an effective volume of 0.062 cm3 produced a maximum of 44.5 μW, or 0.717mW/cm3 at its resonant frequency of 90 Hz. The optimal coating mixture had the composition of 59.9%FNP + 40% ZnO + 1% Resin Binder. The coating utilizes the opto-magneto-electrical properties of ZnO and Magnetic properties of FNP. To further enhance the output, the magneto-electric (ME) effect was increased by subjecting the composite to magnetic field where coating acts as a magnetostrictive material. For the effective volume of 0.0062 cm 3, the composite produced a maximum of 68.5 μW, or 1.11mW/cm 3 at its resonant frequency of 90 Hz at 160 gauss. The optimal coating mixture had the composition of 59.9% FNP + 40% ZnO + 1% Resin Binder. This research also focused on improving the efficiency of solar cells by utilizing the magnetic effect along with gas plasma etching to improve the internal reflection

  6. Energy harvesting from arterial blood pressure for powering embedded brain sensors

    Science.gov (United States)

    Nanda, Aditya; Karami, M. Amin

    2016-04-01

    This paper investigates energy harvesting from arterial blood pressure via the piezoelectric effect by using a novel streaked cylinder geometry for the purpose of powering embedded micro-sensors in the brain. Initially, we look at the energy harvested by a piezoelectric cylinder placed inside an artery acted upon by blood pressure. Such an arrangement would be tantamount to constructing a stent out of piezoelectric materials. A stent is a cylinder placed in veins and arteries to prevent obstruction in blood flow. The governing equations of a conductor coated piezoelectric cylinder are obtained using Hamilton's principle. Pressure acting in arteries is radially directed and this is used to simplify the modal analysis and obtain the transfer function relating pressure to the induced voltage across the surface of the harvester. The power harvested by the cylindrical harvester is obtained for different shunt resistances. Radially directed pressure occurs elsewhere and we also look at harvesting energy from oil flow in pipelines. Although the energy harvested by the cylindrical energy harvester is significant at resonance, the natural frequency of the system is found to be very high. To decrease the natural frequency, we propose a novel streaked stent design by cutting it along the length, transforming it to a curved plate and decreasing the natural frequency. The governing equations corresponding to the new geometry are derived using Hamilton's principle and modal analysis is used to obtain the transfer function.

  7. Thermoelectric Air/Soil Energy-Harvesting Device

    Science.gov (United States)

    Snyder, Jeffrey; Fleurial, Jean-Pierre; Lawrence, Eric

    2005-01-01

    A proposed thermoelectric device would exploit natural temperature differences between air and soil to harvest small amounts of electric energy. Because the air/soil temperature difference fluctuates between nighttime and daytime, it is almost never zero, and so there is almost always some energy available for harvesting. Unlike photovoltaic cells, the proposed device could operate in the absence of sunlight. Unlike a Stirling engine, which could be designed to extract energy from the air/soil temperature difference, the proposed device would contain no moving parts. The main attractive feature of the proposed device would be high reliability. In a typical application, this device would be used for low-power charging of a battery that would, in turn, supply high power at brief, infrequent intervals for operating an instrumentation package containing sensors and communication circuits. The device (see figure) would include a heat exchanger buried in soil and connected to a heat pipe extending up to a short distance above the ground surface. A thermoelectric microgenerator (TEMG) would be mounted on top of the heat pipe. The TEMG could be of an advanced type, now under development, that could maintain high (relative to prior thermoelectric generators) power densities at small temperature differentials. A heat exchanger exposed to the air would be mounted on top of the TEMG. It would not matter whether the air was warmer than the soil or the soil warmer than the air: as long as there was a nonzero temperature difference, heat would flow through the device and electricity would be generated. A study of factors that could affect the design and operation of the device has been performed. These factors include the thermal conductances of the soil, the components of the device, the contacts between the components of the device, and the interfaces between the heat exchangers and their environments. The study included experiments that were performed on a model of the device

  8. Development and Validation of an Enhanced Coupled-Field Model for PZT Cantilever Bimorph Energy Harvester

    Directory of Open Access Journals (Sweden)

    Long Zhang

    2013-01-01

    Full Text Available The power source with the limited life span has motivated the development of the energy harvesters that can scavenge the ambient environment energy and convert it into the electrical energy. With the coupled field characteristics of structure to electricity, piezoelectric energy harvesters are under consideration as a means of converting the mechanical energy to the electrical energy, with the goal of realizing completely self-powered sensor systems. In this paper, two previous models in the literatures for predicting the open-circuit and close-circuit voltages of a piezoelectric cantilever bimorph (PCB energy harvester are first described, that is, the mechanical equivalent spring mass-damper model and the electrical equivalent circuit model. Then, the development of an enhanced coupled field model for the PCB energy harvester based on another previous model in the literature using a conservation of energy method is presented. Further, the laboratory experiments are carried out to evaluate the enhanced coupled field model and the other two previous models in the literatures. The comparison results show that the enhanced coupled field model can better predict the open-circuit and close-circuit voltages of the PCB energy harvester with a proof mass bonded at the free end of the structure in order to increase the energy-harvesting level of the system.

  9. Broadening the Frequency Bandwidth of Piezoelectric Energy Harvesters Using Coupled Linear Resonators

    Science.gov (United States)

    Sadeqi, Soheil

    The desire to reduce power consumption of current integrated circuits has led design engineers to focus on harvesting energy from free ambient sources such as vibrations. The energy harvested this way can eliminate the need for battery replacement, particularly, in low-energy remote sensing and wireless devices. Currently, most vibration-based energy harvesters are designed as linear resonators, therefore, they have a narrow resonance frequency. The optimal performance of such harvesters is achieved only when their resonance frequency is matched with the ambient excitation. In practice, however, a slight shift of the excitation frequency will cause a dramatic reduction in their performance. In the majority of cases, the ambient vibrations are totally random with their energy distributed over a wide frequency spectrum. Thus, developing techniques to extend the bandwidth of vibration-based energy harvesters has become an important field of research in energy harvesting systems. This thesis first reviews the broadband vibration-based energy harvesting techniques currently known in some detail with regard to their merits and applicability under different circumstances. After that, the design, fabrication, modeling and characterization of three new piezoelectric-based energy harvesting mechanism, built typically for rotary motion applications, is discussed. A step-by-step procedure is followed in order to broaden the bandwidth of such energy harvesters by introducing a coupled spring-mass system attached to a PZT beam undergoing rotary motion. It is shown that the new strategies can indeed give rise to a wide-band frequency response making it possible to fine-tune their dynamical response. The numerical results are shown to be in good agreement with the experimental data as far as the frequency response is concerned.

  10. Harvesting Broad Frequency Band Blue Energy by a Triboelectric-Electromagnetic Hybrid Nanogenerator.

    Science.gov (United States)

    Wen, Zhen; Guo, Hengyu; Zi, Yunlong; Yeh, Min-Hsin; Wang, Xin; Deng, Jianan; Wang, Jie; Li, Shengming; Hu, Chenguo; Zhu, Liping; Wang, Zhong Lin

    2016-07-26

    Ocean wave associated energy is huge, but it has little use toward world energy. Although such blue energy is capable of meeting all of our energy needs, there is no effective way to harvest it due to its low frequency and irregular amplitude, which may restrict the application of traditional power generators. In this work, we report a hybrid nanogenerator that consists of a spiral-interdigitated-electrode triboelectric nanogenerator (S-TENG) and a wrap-around electromagnetic generator (W-EMG) for harvesting ocean energy. In this design, the S-TENG can be fully isolated from the external environment through packaging and indirectly driven by the noncontact attractive forces between pairs of magnets, and W-EMG can be easily hybridized. Notably, the hybrid nanogenerator could generate electricity under either rotation mode or fluctuation mode to collect energy in ocean tide, current, and wave energy due to the unique structural design. In addition, the characteristics and advantages of outputs indicate that the S-TENG is irreplaceable for harvesting low rotation speeds (blue energy, while W-EMG is able to produce larger output at high frequencies (>10 Hz). The complementary output can be maximized and hybridized for harvesting energy in a broad frequency range. Finally, a single hybrid nanogenerator unit was demonstrated to harvest blue energy as a practical power source to drive several LEDs under different simulated water wave conditions. We also proposed a blue energy harvesting system floating on the ocean surface that could simultaneously harvest wind, solar, and wave energy. The proposed hybrid nanogenerator renders an effective and sustainable progress in practical applications of the hybrid nanogenerator toward harvesting water wave energy offered by nature.

  11. A hybrid indoor ambient light and vibration energy harvester for wireless sensor nodes.

    Science.gov (United States)

    Yu, Hua; Yue, Qiuqin; Zhou, Jielin; Wang, Wei

    2014-05-19

    To take advantage of applications where both light and vibration energy are available, a hybrid indoor ambient light and vibration energy harvesting scheme is proposed in this paper. This scheme uses only one power conditioning circuit to condition the combined output power harvested from both energy sources so as to reduce the power dissipation. In order to more accurately predict the instantaneous power harvested from the solar panel, an improved five-parameter model for small-scale solar panel applying in low light illumination is presented. The output voltage is increased by using the MEMS piezoelectric cantilever arrays architecture. It overcomes the disadvantage of traditional MEMS vibration energy harvester with low voltage output. The implementation of the maximum power point tracking (MPPT) for indoor ambient light is implemented using analog discrete components, which improves the whole harvester efficiency significantly compared to the digital signal processor. The output power of the vibration energy harvester is improved by using the impedance matching technique. An efficient mechanism of energy accumulation and bleed-off is also discussed. Experiment results obtained from an amorphous-silicon (a-Si) solar panel of 4.8 × 2.0 cm2 and a fabricated piezoelectric MEMS generator of 11 × 12.4 mm2 show that the hybrid energy harvester achieves a maximum efficiency around 76.7%.

  12. A Hybrid Indoor Ambient Light and Vibration Energy Harvester for Wireless Sensor Nodes

    Directory of Open Access Journals (Sweden)

    Hua Yu

    2014-05-01

    Full Text Available To take advantage of applications where both light and vibration energy are available, a hybrid indoor ambient light and vibration energy harvesting scheme is proposed in this paper. This scheme uses only one power conditioning circuit to condition the combined output power harvested from both energy sources so as to reduce the power dissipation. In order to more accurately predict the instantaneous power harvested from the solar panel, an improved five-parameter model for small-scale solar panel applying in low light illumination is presented. The output voltage is increased by using the MEMS piezoelectric cantilever arrays architecture. It overcomes the disadvantage of traditional MEMS vibration energy harvester with low voltage output. The implementation of the maximum power point tracking (MPPT for indoor ambient light is implemented using analog discrete components, which improves the whole harvester efficiency significantly compared to the digital signal processor. The output power of the vibration energy harvester is improved by using the impedance matching technique. An efficient mechanism of energy accumulation and bleed-off is also discussed. Experiment results obtained from an amorphous-silicon (a-Si solar panel of 4.8 × 2.0 cm2 and a fabricated piezoelectric MEMS generator of 11 × 12.4 mm2 show that the hybrid energy harvester achieves a maximum efficiency around 76.7%.

  13. Manufacturing and Characterization of a Thermoelectric Energy Harvester Using the CMOS-MEMS Technology

    Directory of Open Access Journals (Sweden)

    Shih-Wen Peng

    2015-10-01

    Full Text Available The fabrication and characterization of a thermoelectric energy harvester using the complementary metal oxide semiconductor (CMOS-microelectromechanical system (MEMS technology were presented. The thermoelectric energy harvester is composed of eight circular energy harvesting cells, and each cell consists of 25 thermocouples in series. The thermocouples are made of p-type and n-type polysilicons. The output power of the energy harvester relies on the number of the thermocouples. In order to enhance the output power, the energy harvester increases the thermocouple number per area. The energy harvester requires a post-CMOS process to etch the sacrificial silicon dioxide layer and the silicon substrate to release the suspended structures of hot part. The experimental results show that the energy harvester has an output voltage per area of 0.178 mV·mm−2·K−1 and a power factor of 1.47 × 10−3 pW·mm−2·K−2.

  14. EHRA: Specification and Analysis of Energy-Harvesting Wireless Sensor Networks

    DEFF Research Database (Denmark)

    Dung, Phan Anh; Hansen, Michael Reichhardt; Madsen, Jan

    2014-01-01

    Although energy consumption of wireless sensor network has been studied extensively, we are far behind in understanding the dynamics of the power consumption along with energy production using harvesters. We introduce Energy Harvesting Routing Analysis (EHRA) as a formal modelling framework...... to study wireless sensor networks (WSN) with energy-harvesting capabilities. The purpose of the framework is to analyze WSNs at a high level of abstraction, that is, before the protocols are implemented and before the WSN is deployed. The conceptual basis of EHRA comprises the environment, the medium...... is developed as a simulator implemented using the functional programming language F#. This simulator is used to analyze global properties of WSNs such as network fragmentation,routing trends, and energy profiles for the nodes. Three routing protocols, with a progression in the energy-harvesting awareness...

  15. Application review of dielectric electroactive polymers (DEAPs) and piezoelectric materials for vibration energy harvesting

    Science.gov (United States)

    Yuan, Xuan; Changgeng, Shuai; Yan, Gao; Zhenghong, Zhao

    2016-09-01

    This paper reviews recent advances in vibration energy harvesting with particular emphasis on the solutions by using dielectric electroactive polymers (DEAPs) and piezoelectric materials. These smart materials are in essence capable of converting wasted vibration energy in the environment to usable electrical energy. Much previous researches have been devoted to studying the technology of harvesting mechanical energy using piezoelectric materials. The recent introduction of the DEAPs that exhibits large displacements under electric activation has led to their consideration as promising replacement for conventional piezoelectric materials. The properties of the two materials are described in this paper together with a comparison of their performance in relation with energy harvesting. Finally comparisons are made in the applications of vibration energy harvesting using these two materials. This paper has been written with reference to a large number of published papers listed in the reference section.

  16. Underwater energy harvesting from a turbine hosting ionic polymer metal composites

    Science.gov (United States)

    Cellini, Filippo; Pounds, Jason; Peterson, Sean D.; Porfiri, Maurizio

    2014-08-01

    In this study, we explore the possibility of energy harvesting from fluid flow through a turbine hosting ionic polymer metal composites (IPMCs). Specifically, IPMC harvesters are embedded in the blades of a small-scale vertical axis water turbine to convert flow kinetics into electrical power via low-frequency flow-induced IPMC deformations. An in-house fabricated Savonius-Darrieus hybrid active turbine with three IPMCs is tested in a laboratory water tunnel to estimate the energy harvesting capabilities of the device as a function of the shunting electrical load. The turbine is shown to harvest a few nanowatt from a mean flow of 0.43\\;m\\;{{s}^{-1}} for shunting resistances in the range 100-1000\\;\\Omega . To establish a first understanding of the energy harvesting device, we propose a quasi-static hydroelastic model for the bending of the IPMCs and we utilize a black-box model to study their electromechanical response.

  17. A mechanical energy harvested magnetorheological damper with linear-rotary motion converter

    Science.gov (United States)

    Chu, Ki Sum; Zou, Li; Liao, Wei-Hsin

    2016-04-01

    Magnetorheological (MR) dampers are promising to substitute traditional oil dampers because of adaptive properties of MR fluids. During vibration, significant energy is wasted due to the energy dissipation in the damper. Meanwhile, for conventional MR damping systems, extra power supply is needed. In this paper, a new energy harvester is designed in an MR damper that integrates controllable damping and energy harvesting functions into one device. The energy harvesting part of this MR damper has a unique mechanism converting linear motion to rotary motion that would be more stable and cost effective when compared to other mechanical transmissions. A Maxon motor is used as a power generator to convert the mechanical energy into electrical energy to supply power for the MR damping system. Compared to conventional approaches, there are several advantages in such an integrated device, including weight reduction, ease in installation with less maintenance. A mechanical energy harvested MR damper with linear-rotary motion converter and motion rectifier is designed, fabricated, and tested. Experimental studies on controllable damping force and harvested energy are performed with different transmissions. This energy harvesting MR damper would be suitable to vehicle suspensions, civil structures, and smart prostheses.

  18. Analysis and experimental verification of electroacoustic wave energy harvesting in a coupled piezoelectric plate-harvester system

    Science.gov (United States)

    Darabi, Amir; Leamy, Michael J.

    2017-03-01

    This paper introduces an analytical framework for predicting wave energy harvested by a circular piezoelectric disk attached to a thin plate. An harmonic point source excitation generates waves that are then incident on a piezoelectric disk—summing responses due to all such excitation enables general forcing profiles to be considered. The analysis approach decomposes the coupled system into two subdomains, one being the piezoelectric disk, and the other an infinite plate for which a Green's function is readily available. Interaction forces between the two subdomains couple the problems and lead to a closed-form solution for the propagation, transmission, and reflection of waves over the entire domain. In addition, the voltage generated by the harvester is calculated using coupled electromechanical equations. The analysis approach is first validated by comparing predicted response quantities to those computed using numerical simulations, documenting good agreement. The system is then studied in the frequency domain and the optimum harvester resistance is found for generating the most electrical power. Representative experiments are carried out to demonstrate the validity of the analytical approach and verify the harvested power versus resistance trend.

  19. Fundamental Studies On Development Of MHD (Magnetohydrodynamic) Generator Implement On Wave Energy Harvesting

    Science.gov (United States)

    Majid, M. F. M. A.; Apandi, Muhamad Al-Hakim Md; Sabri, M.; Shahril, K.

    2016-02-01

    As increasing of agricultural and industrial activities each year has led to an increasing in demand for energy. Possibility in the future, the country was not able to offer a lot of energy and power demand. This means that we need to focus on renewable energy to supply the demand for energy. Energy harvesting is among a method that can contribute on the renewable energy. MHD power generator is a new way to harvest the energy especially Ocean wave energy. An experimental investigation was conducted to explore performance of MHD generator. The effect of intensity of NaCl Solution (Sea Water), flow rate of NaCl solution, magnetic strength and magnet position to the current produce was analyzed. The result shows that each factor is give a significant effect to the current produce, because of that each factor need to consider on develop of MHD generator to harvest the wave energy as an alternative way to support the demand for energy.

  20. An Energy-Efficient Scheme for Multirelay Cooperative Networks with Energy Harvesting

    Directory of Open Access Journals (Sweden)

    Dingcheng Yang

    2016-01-01

    Full Text Available This study investigates an energy-efficient scheme in multirelay cooperative networks with energy harvesting where multiple sessions need to communicate with each other via the relay node. A two-step optimal method is proposed which maximizes the system energy efficiency, while taking into account the receiver circuit energy consumption. Firstly, the optimal power allocation for relay nodes is determined to maximize the system throughput; this is based on directional water-filling algorithm. Secondly, using quantum particle swarm optimization (QPSO, a joint relay node selection and session grouping optimization is proposed. With this algorithm, sessions can be classified into multiple groups that are assisted by the specific relay node with the maximum energy efficiency. This approach leads to a better global optimization in searching ability and efficiency. Simulation results show that the proposed scheme can improve the energy efficiency effectively compared with direct transmission and opportunistic relay-selected cooperative transmission.

  1. Experimental investigation of broadband energy harvesting of a bi-stable composite piezoelectric plate

    Science.gov (United States)

    Pan, Diankun; Ma, Benbiao; Dai, Fuhong

    2017-03-01

    In this work, a bi-stable vibration energy harvester is presented to scavenge energy from ambient vibrations over a wide frequency range. This bi-stable harvester consists of a bi-stable hybrid composite plate as host structure and several pieces of piezoelectric ceramics. Three linear harvesters with the same geometry were employed as the control samples to illustrate the advantages of this bi-stable harvester. The voltage–frequency responses were measured with different g-level excitations, and the output powers across various resistances were measured at different frequencies and accelerations. Unlike the linear harvesters which are effective only near their natural frequencies, the obvious nonlinearities of this bi-stable harvester broaden its working bandwidth. Additionally, the characteristics of this bi-stable host structure contribute to the output power. Under the same condition, when this bi-stable harvester is under cross-well oscillation pattern the maximum output powers are several times higher than those of the linear harvesters. The measured highest output power of this bi-stable harvester is 36.2 mW with 38 Hz frequency and 5g acceleration (g = 9.8 m s‑2).

  2. Multi-directional energy harvesting by piezoelectric cantilever-pendulum with internal resonance

    Energy Technology Data Exchange (ETDEWEB)

    Xu, J.; Tang, J., E-mail: jtang@engr.uconn.edu [Department of Mechanical Engineering, The University of Connecticut, Storrs, Connecticut 06269 (United States)

    2015-11-23

    This letter reports a piezoelectric cantilever-pendulum design for multi-directional energy harvesting. A pendulum is attached to the tip of a piezoelectric cantilever-type energy harvester. This design aims at taking advantage of the nonlinear coupling between the pendulum motion in 3-dimensional space and the beam bending vibration at resonances. Experimental studies indicate that, under properly chosen parameters, 1:2 internal resonance can be induced, which enables the multi-directional energy harvesting with a single cantilever. The advantages of the design with respect to traditional piezoelectric cantilever are examined.

  3. BROADBAND CONCEPT OF ENERGY HARVESTING IN BEAM VIBRATING SYSTEMS FOR POWERING SENSORS

    Directory of Open Access Journals (Sweden)

    Andrzej Rysak

    2014-09-01

    Full Text Available Recent demand for powering small sensors for wireless health monitoring triggered activities in the field of small size efficient energy harvesting devices. We examine energy harvesting in an aluminium beam with a piezoceramic patch subjected to kinematic harmonic excitation and impacts. Due to a mechanical stopper applied, inducing a hardening effect in the spring characteristic of the beam resonator, we observed a broader frequency range for the fairly large power output. Impact nonlinearities caused sensitivity to initial conditions and appearance of multiple solutions. The occurrence of resonant solution associated with impacts increased efficiency of the energy harvesting process.

  4. Bias-Flip Technique for Frequency Tuning of Piezo-Electric Energy Harvesting Devices

    Directory of Open Access Journals (Sweden)

    Jianguo Ma

    2013-06-01

    Full Text Available Devices that harvest electrical energy from mechanical vibrations have the problem that the frequency of the source vibration is often not matched to the resonant frequency of the energy harvesting device. Manufacturing tolerances make it difficult to match the Energy Harvesting Device (EHD resonant frequency to the source vibration frequency, and the source vibration frequency may vary with time. Previous work has recognized that it is possible to tune the resonant frequency of an EHD using a tunable, reactive impedance at the output of the device. The present paper develops the theory of electrical tuning, and proposes the Bias-Flip (BF technique, to implement this tunable, reactive impedance.

  5. Energy harvesting from dancing: for broadening in participation in STEM fields

    Science.gov (United States)

    Hamidi, Armita; Tadesse, Yonas

    2016-04-01

    Energy harvesting from structure vibration, human motion or environmental source has been the focus of researchers in the past few decades. This paper proposes a novel design that is suitable to harvest energy from human motions such as dancing or physical exercise and use the device to engage young students in Science, Technology, Engineering and Math (STEM) fields and outreach activities. The energy harvester (EH) device was designed for a dominant human operational frequency range of 1-5 Hz and it can be wearable by human. We proposed to incorporate different genres of music coupled with energy harvesting technologies for motivation and energy generation. Students will learn both science and art together, since the energy harvesting requires understanding basic physical phenomena and the art enables various physical movements that imparts the largest motion transfer to the EH device. Therefore, the systems are coupled to each other. Young people follow music updates more than robotics or energy harvesting researches. Most popular videos on YouTube and VEVO are viewed more than 100 million times. Perhaps, integrating the energy harvesting research with music or physical exercise might enhance students' engagement in science, and needs investigation. A multimodal energy harvester consisting of piezoelectric and electromagnetic subsystems, which can be wearable in the leg, is proposed in this study. Three piezoelectric cantilever beams having permanent magnets at the ends are connected to a base through a slip ring. Stationary electromagnetic coils are installed in the base and connected in series. Whenever the device is driven by any oscillation parallel to the base, the unbalanced rotor will rotate generating energy across the stationary coils in the base. In another case, if the device is driven by an oscillation perpendicular to the base, a stress will be induced within the cantilever beams generating energy across the piezoelectric materials.

  6. Self-reverse-biased solar panel optical receiver for simultaneous visible light communication and energy harvesting.

    Science.gov (United States)

    Shin, Won-Ho; Yang, Se-Hoon; Kwon, Do-Hoon; Han, Sang-Kook

    2016-10-31

    We propose a self-reverse-biased solar panel optical receiver for energy harvesting and visible light communication. Since the solar panel converts an optical component into an electrical component, it provides both energy harvesting and communication. The signal component can be separated from the direct current component, and these components are used for communication and energy harvesting. We employed a self-reverse-biased receiver circuit to improve the communication and energy harvesting performance. The reverse bias on the solar panel improves the responsivity and response time. The proposed system achieved 17.05 mbps discrete multitone transmission with a bit error rate of 1.1 x 10-3 and enhanced solar energy conversion efficiency.

  7. Parameter study and optimization for piezoelectric energy harvester for TPMS considering speed variation

    Science.gov (United States)

    Toghi Eshghi, Amin; Lee, Soobum; Lee, Hanmin; Kim, Young-Cheol

    2016-04-01

    In this paper, we perform design parameter study and design optimization for a piezoelectric energy harvester considering vehicle speed variation. Initially, a FEM model using ANSYS is developed to appraise the performance of a piezoelectric harvester in a rotating tire. The energy harvester proposed here uses the vertical deformation at contact patch area from the car weight and centrifugal acceleration. This harvester is composed of a beam which is clamped at both ends and a piezoelectric material is attached on the top of that. The piezoelectric material possesses the 31 mode of transduction in which the direction of applied field is perpendicular to that of the electric field. To optimize the harvester performance, we would change the geometrical parameters of the harvester to obtain the maximum power. One of the main challenges in the design process is obtaining the required power while considering the constraints for harvester weight and volume. These two concerns are addressed in this paper. Since the final goal of this study is the development of an energy harvester with a wireless sensor system installed in a real car, the real time data for varied velocity of a vehicle are taken into account for power measurements. This study concludes that the proposed design is applicable to wireless tire sensor systems.

  8. Recent Advances in Energy Harvesting Technologies for Structural Health Monitoring Applications

    Directory of Open Access Journals (Sweden)

    Joseph Davidson

    2014-01-01

    Full Text Available This paper reviews recent developments in energy harvesting technologies for structural health monitoring applications. Many industries have a great deal of interest in obtaining technology that can be used to monitor the health of machinery and structures. In particular, the need for autonomous monitoring of structures has been ever-increasing in recent years. Autonomous SHM systems typically include embedded sensors, data acquisition, wireless communication, and energy harvesting systems. Among all of these components, this paper focuses on the energy harvesting technologies. Since low-power sensors and wireless communications are used in newer SHM systems, a number of researchers have recently investigated techniques to extract energy from the local environment to power these stand-alone systems. Ambient energy sources include vibration, thermal gradients, solar, wind, pressure, etc. If the structure has a rich enough loading, then it may be possible to extract the needed power directly from the structure itself. Harvesting energy using piezoelectric materials by converting applied stress to electricity is most common. Other methods to harvest energy such as electromagnetic, magnetostrictive, or thermoelectric generator are also reviewed. Lastly, an energy harvester with frequency tuning capability is demonstrated.

  9. Increased power to weight ratio of piezoelectric energy harvesters through integration of cellular honeycomb structures

    Science.gov (United States)

    Chandrasekharan, N.; Thompson, L. L.

    2016-04-01

    The limitations posed by batteries have compelled the need to investigate energy harvesting methods to power small electronic devices that require very low operational power. Vibration based energy harvesting methods with piezoelectric transduction in particular has been shown to possess potential towards energy harvesters replacing batteries. Current piezoelectric energy harvesters exhibit considerably lower power to weight ratio or specific power when compared to batteries the harvesters seek to replace. To attain the goal of battery-less self-sustainable device operation the power to weight ratio gap between piezoelectric energy harvesters and batteries need to be bridged. In this paper the potential of integrating lightweight honeycomb structures with existing piezoelectric device configurations (bimorph) towards achieving higher specific power is investigated. It is shown in this study that at low excitation frequency ranges, replacing the solid continuous substrate of conventional bimorph with honeycomb structures of the same material results in a significant increase in power to weight ratio of the piezoelectric harvester. At higher driving frequency ranges it is shown that unlike the traditional piezoelectric bimorph with solid continuous substrate, the honeycomb substrate bimorph can preserve optimum global design parameters through manipulation of honeycomb unit cell parameters. Increased operating lifetime and design flexibility of the honeycomb core piezoelectric bimorph is demonstrated as unit cell parameters of the honeycomb structures can be manipulated to alter mass and stiffness properties of the substrate, resulting in unit cell parameter significantly influencing power generation.

  10. Microfabrication and integration of a sol-gel PZT folded spring energy harvester.

    Science.gov (United States)

    Lueke, Jonathan; Badr, Ahmed; Lou, Edmond; Moussa, Walied A

    2015-05-26

    This paper presents the methodology and challenges experienced in the microfabrication, packaging, and integration of a fixed-fixed folded spring piezoelectric energy harvester. A variety of challenges were overcome in the fabrication of the energy harvesters, such as the diagnosis and rectification of sol-gel PZT film quality and adhesion issues. A packaging and integration methodology was developed to allow for the characterizing the harvesters under a base vibration. The conditioning circuitry developed allowed for a complete energy harvesting system, consisting a harvester, a voltage doubler, a voltage regulator and a NiMH battery. A feasibility study was undertaken with the designed conditioning circuitry to determine the effect of the input parameters on the overall performance of the circuit. It was found that the maximum efficiency does not correlate to the maximum charging current supplied to the battery. The efficiency and charging current must be balanced to achieve a high output and a reasonable output current. The development of the complete energy harvesting system allows for the direct integration of the energy harvesting technology into existing power management schemes for wireless sensing.

  11. Microfabrication and Integration of a Sol-Gel PZT Folded Spring Energy Harvester

    Directory of Open Access Journals (Sweden)

    Jonathan Lueke

    2015-05-01

    Full Text Available This paper presents the methodology and challenges experienced in the microfabrication, packaging, and integration of a fixed-fixed folded spring piezoelectric energy harvester. A variety of challenges were overcome in the fabrication of the energy harvesters, such as the diagnosis and rectification of sol-gel PZT film quality and adhesion issues. A packaging and integration methodology was developed to allow for the characterizing the harvesters under a base vibration. The conditioning circuitry developed allowed for a complete energy harvesting system, consisting a harvester, a voltage doubler, a voltage regulator and a NiMH battery. A feasibility study was undertaken with the designed conditioning circuitry to determine the effect of the input parameters on the overall performance of the circuit. It was found that the maximum efficiency does not correlate to the maximum charging current supplied to the battery. The efficiency and charging current must be balanced to achieve a high output and a reasonable output current. The development of the complete energy harvesting system allows for the direct integration of the energy harvesting technology into existing power management schemes for wireless sensing.

  12. Biomechanics of Wheat/Barley Straw and Corn Stover

    Energy Technology Data Exchange (ETDEWEB)

    Christopher T. Wright; Peter A. Pryfogle; Nathan A. Stevens; Eric D. Steffler; J. Richard Hess; Thomas H. Ulrich

    2005-03-01

    The lack of understanding of the mechanical characteristics of cellulosic feedstocks is a limiting factor in economically collecting and processing crop residues, primarily wheat and barley stems and corn stover. Several testing methods, including compression, tension, and bend have been investigated to increase our understanding of the biomechanical behavior of cellulosic feedstocks. Biomechanical data from these tests can provide required input to numerical models and help advance harvesting, handling, and processing techniques. In addition, integrating the models with the complete data set from this study can identify potential tools for manipulating the biomechanical properties of plant varieties in such a manner as to optimize their physical characteristics to produce higher value biomass and more energy efficient harvesting practices.

  13. Light harvesting via energy transfer in the dye solar cell

    Energy Technology Data Exchange (ETDEWEB)

    Siegers, Conrad

    2007-11-09

    The PhD-thesis ''Light Harvesting via Energy Transfer in the Dye Solar Cell'' (University of Freiburg, July 2007) describes the conceptual design, synthesis and testing of energy donor acceptor sensitizers for the dye solar cell (DSC). Under monochromatic illumination solar cells sensitized with the novel donor acceptor systems revealed a higher power conversion efficiency than cells containing exclusively the acceptor component. The following approach led to this conclusion: (i) the choice of suitable chromophores as energy donor and acceptor moieties according to the Foerster-theory, (ii) the synthesis of different donor acceptor systems, (iii) the development of a methodology allowing the quantification of energy transfer within dye solar cells, and (iv) the evaluation of characteristics of DSCs that were sensitized with the different donor acceptor systems. The acceptor chromophores used in this work were derived from [Ru(dcbpy)2acac]Cl (dcbpy = 4,4'-dicarboxy-2,2'-bipyridin, acac = acetylacetonato). This complex offered the opportunity to introduce substituents at the acac-ligand's terminal CH3 groups without significantly affecting its excellent photoelectrochemical properties. Alkylated 4-amino-1,8-naphthalimides (termed Fluorols in the following) were used as energy donor chromophores. This class of compounds fulfils the requirements for efficient energy transfer to [Ru(dcbpy)2acac]Cl. Covalently linking donor and acceptor chromophores to one another was achieved by two different concepts. A dyad comprising one donor and one acceptor chromophore was synthesized by subsequent hydrosilylation steps of an olefin-bearing donor and an acceptor precursor to the dihydrosilane HSiMe2-CH2CH2-SiMe2H. A series of polymers comprising multiple donor and acceptor units was made by the addition of alkyne-bearing chromophores to hyperbranched polyglycerol azide (''Click-chemistry''). In this series the donor acceptor

  14. Energy harvesting by means of flow-induced vibrations on aerospace vehicles

    Science.gov (United States)

    Li, Daochun; Wu, Yining; Da Ronch, Andrea; Xiang, Jinwu

    2016-10-01

    This paper reviews the design, implementation, and demonstration of energy harvesting devices that exploit flow-induced vibrations as the main source of energy. Starting with a presentation of various concepts of energy harvesters that are designed to benefit from a general class of flow-induced vibrations, specific attention is then given at those technologies that may offer, today or in the near future, a potential benefit to extend the operational capabilities and to monitor critical parameters of unmanned aerial vehicles. Various phenomena characterized by flow-induced vibrations are discussed, including limit cycle oscillations of plates and wing sections, vortex-induced and galloping oscillations of bluff bodies, vortex-induced vibrations of downstream structures, and atmospheric turbulence and gusts. It was found that linear or linearized modeling approaches are commonly employed to support the design phase of energy harvesters. As a result, highly nonlinear and coupled phenomena that characterize flow-induced vibrations are neglected in the design process. The Authors encourage a shift in the current design paradigm: considering coupled nonlinear phenomena, and adequate modeling tools to support their analysis, from a design limitation to a design opportunity. Special emphasis is placed on identifying designs and implementations applicable to aircraft configurations. Application fields of flow-induced vibrations-based energy harvesters are discussed including power supply for wireless sensor networks and simultaneous energy harvest and control. A large body of work on energy harvesters is included in this review journal. Whereas most of the references claim direct applications to unmanned aerial vehicles, it is apparent that, in most of the cases presented, the working principles and characteristics of the energy harvesters are incompatible with any aerospace applications. Finally, the challenges that hold back the integration of energy harvesting

  15. Powering Autonomous Sensors An Integral Approach with Focus on Solar and RF Energy Harvesting

    CERN Document Server

    Penella-López, María Teresa

    2011-01-01

    Autonomous sensors transmit data and power their electronics without using cables. They can be found in e.g. wireless sensor networks (WSNs) or remote acquisition systems. Although primary batteries provide a simple design for powering autonomous sensors, they present several limitations such as limited capacity and power density, and difficulty in predicting their condition and state of charge. An alternative is to extract energy from the ambient (energy harvesting). However, the reduced dimensions of most autonomous sensors lead to a low level of available power from the energy transducer. Thus, efficient methods and circuits to manage and gather the energy are a must. An integral approach for powering autonomous sensors by considering both primary batteries and energy harvesters is presented. Two rather different forms of energy harvesting are also dealt with: optical (or solar) and radiofrequency (RF). Optical energy provides high energy density, especially outdoors, whereas RF remote powering is possibly...

  16. Integrated multilayered triboelectric nanogenerator for harvesting biomechanical energy from human motions.

    Science.gov (United States)

    Bai, Peng; Zhu, Guang; Lin, Zong-Hong; Jing, Qingshen; Chen, Jun; Zhang, Gong; Ma, Jusheng; Wang, Zhong Lin

    2013-04-23

    We demonstrate a new flexible multilayered triboelectric nanogenerator (TENG) with extremely low cost, simple structure, small size (3.8 cm×3.8 cm×0.95 cm) and lightweight (7 g) by innovatively integrating five layers of units on a single flexible substrate. Owing to the unique structure and nanopore-based surface modification on the metal surface, the instantaneous short-circuit current (Isc) and the open-circuit voltage (Voc) could reach 0.66 mA and 215 V with an instantaneous maximum power density of 9.8 mW/cm2 and 10.24 mW/cm3. This is the first 3D integrated TENG for enhancing the output power. Triggered by press from normal walking, the TENG attached onto a shoe pad was able to instantaneously drive multiple commercial LED bulbs. With the flexible structure, the TENG can be further integrated into clothes or even attached onto human body without introducing sensible obstruction and discomfort to human motions. The novel design of TENG demonstrated here can be applied to potentially achieve self-powered portable electronics.

  17. Mems-based pzt/pzt bimorph thick film vibration energy harvester

    DEFF Research Database (Denmark)

    Xu, Ruichao; Lei, Anders; Dahl-Petersen, Christian

    2011-01-01

    We describe fabrication and characterization of a significantly improved version of a MEMS-based PZT/PZT thick film bimorph vibration energy harvester with an integrated silicon proof mass. The main advantage of bimorph vibration energy harvesters is that strain energy is not lost in mechanical...... support materials since only PZT is strained, and thus it has a potential for significantly higher output power. An improved process scheme for the energy harvester resulted in a robust fabrication process with a record high fabrication yield of 98.6%. Moreover, the robust fabrication process allowed...... a high pressure treatment of the screen printed PZT thick films prior to sintering, improving the PZT thick film performance and harvester power output reaches 37.1 μW at 1 g....

  18. Fabrication and characterization of MEMS-based PZT/PZT bimorph thick film vibration energy harvesters

    DEFF Research Database (Denmark)

    Xu, Ruichao; Lei, Anders; Dahl-Petersen, Christian

    2012-01-01

    We describe the fabrication and characterization of a significantly improved version of a microelectromechanical system-based PZT/PZT thick film bimorph vibration energy harvester with an integrated silicon proof mass; the harvester is fabricated in a fully monolithic process. The main advantage...... of bimorph vibration energy harvesters is that strain energy is not lost in mechanical support materials since only Pb(ZrxTi1-x)O3 (PZT) is strained; as a result, the effective system coupling coefficient is increased, and thus a potential for significantly higher output power is released. In addition, when...... the two layers are connected in series, the output voltage is increased, and as a result the relative power loss in the necessary rectifying circuit is reduced. We describe an improved process scheme for the energy harvester, which resulted in a robust fabrication process with a record high fabrication...

  19. Effects of introducing nonlinear components for a random excited hybrid energy harvester

    Science.gov (United States)

    Zhou, Xiaoya; Gao, Shiqiao; Liu, Haipeng; Guan, Yanwei

    2017-01-01

    This work is mainly devoted to discussing the effects of introducing nonlinear components for a hybrid energy harvester under random excitation. For two different types of nonlinear hybrid energy harvesters subjected to random excitation, the analytical solutions of the mean output power, voltage and current are derived from Fokker-Planck (FP) equations. Monte Carlo simulation exhibits qualitative agreement with FP theory, showing that load values and excitation’s spectral density have an effect on the total mean output power, piezoelectric (PE) power and electromagnetic power. Nonlinear components affect output characteristics only when the PE capacitance of the hybrid energy harvester is non-negligible. Besides, it is also demonstrated that for this type of nonlinear hybrid energy harvesters under random excitation, introducing nonlinear components can improve output performances effectively.

  20. Vacuum-packaged piezoelectric vibration energy harvesters: damping contributions and autonomy for a wireless sensor system

    Science.gov (United States)

    Elfrink, R.; Renaud, M.; Kamel, T. M.; de Nooijer, C.; Jambunathan, M.; Goedbloed, M.; Hohlfeld, D.; Matova, S.; Pop, V.; Caballero, L.; van Schaijk, R.

    2010-10-01

    This paper describes the characterization of thin-film MEMS vibration energy harvesters based on aluminum nitride as piezoelectric material. A record output power of 85 µW is measured. The parasitic-damping and the energy-harvesting performances of unpackaged and packaged devices are investigated. Vacuum and atmospheric pressure levels are considered for the packaged devices. When dealing with packaged devices, it is found that vacuum packaging is essential for maximizing the output power. Therefore, a wafer-scale vacuum package process is developed. The energy harvesters are used to power a small prototype (1 cm3 volume) of a wireless autonomous sensor system. The average power consumption of the whole system is less than 10 µW, and it is continuously provided by the vibration energy harvester.