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Sample records for biomechanical energy harvester

  1. 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.

  2. 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.

  3. Myoelectric Control for Adaptable Biomechanical Energy Harvesting.

    Science.gov (United States)

    Selinger, Jessica C; Donelan, J Maxwell

    2016-03-01

    We have designed and tested a myoelectric controller that automatically adapts energy harvesting from the motion of leg joints to match the power available in different walking conditions. To assist muscles in performing negative mechanical work, the controller engages power generation only when estimated joint mechanical power is negative. When engaged, the controller scales its resistive torque in proportion to estimated joint torque, thereby automatically scaling electrical power generation in proportion to the available mechanical power. To produce real-time estimates of joint torque and mechanical power, the controller leverages a simple model that predicts these variables from measured muscle activity and joint angular velocity. We first tested the model using available literature data for a range of walking speeds and found that estimates of knee joint torque and power well match the corresponding literature profiles (torque R(2): 0.73-0.92; power R(2): 0.60-0.94). We then used human subject experiments to test the performance of the entire controller. Over a range of steady state walking speeds and inclines, as well as a number of non-steady state walking conditions, the myoelectric controller accurately identified when the knee generated negative mechanical power, and automatically adjusted the magnitude of electrical power generation. PMID:26841402

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

    OpenAIRE

    Shapiro Amir; Riemer Raziel

    2011-01-01

    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 motio...

  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. 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

  8. 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.

  9. 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

    2015-11-01

    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.

  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

    2015-01-01

    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. PMID:26538375

  11. Harvesting biomechanical energy or carrying batteries? An evaluation method based on a comparison of metabolic power

    OpenAIRE

    Schertzer, Eliran; Riemer, Raziel

    2015-01-01

    Background Harvesting energy from human motion is an innovative alternative to using batteries as a source of electrical power for portable devices. Yet there are no guidelines as to whether energy harvesting should be preferred over batteries. This paper introduces an approach to determine which source of energy should be preferred. The proposed approach compares the metabolic power while harvesting energy and while using batteries (or any other power supply, e.g., solar panels), which provi...

  12. 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

    2016-01-01

    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. PMID:27386560

  13. 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. PMID:27386560

  14. 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.

  15. 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

  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. Millimeter Wave Energy Harvesting

    OpenAIRE

    Khan, Talha Ahmed; Alkhateeb, Ahmed; Heath Jr, Robert W.

    2015-01-01

    The millimeter wave (mmWave) band, which is a prime candidate for 5G cellular networks, seems attractive for wireless energy harvesting. This is because it will feature large antenna arrays as well as extremely dense base station (BS) deployments. The viability of mmWave for energy harvesting though is unclear, due to the differences in propagation characteristics such as extreme sensitivity to building blockages. This paper considers a scenario where low-power devices extract energy and/or i...

  18. 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-

  19. 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...

  20. 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)

  1. 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.

  2. 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.

  3. 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.

  4. 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

  5. Piezoelectric Energy Harvesting Solutions

    Science.gov (United States)

    Caliò, Renato; Rongala, Udaya Bhaskar; Camboni, Domenico; Milazzo, Mario; Stefanini, Cesare; de Petris, Gianluca; Oddo, Calogero Maria

    2014-01-01

    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. PMID:24618725

  6. 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

  7. 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

  8. 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...

  9. 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.

  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. PMID:24187228

  11. RF Energy Harvesting in WSNs

    OpenAIRE

    Tang, Lizzie Zuowen

    2008-01-01

    As a vital factor affecting system cost and lifetime, energy consumption in wireless sensor networks (WSNs) has been paid much attention to. This article reviews existing energy harvesting technology applied in WSNs, and analyzes advantages of harvesting radio frequency (RF) energy in WSNs.

  12. Electrochemically driven mechanical energy harvesting.

    Science.gov (United States)

    Kim, Sangtae; Choi, Soon Ju; Zhao, Kejie; Yang, Hui; Gobbi, Giorgia; Zhang, Sulin; Li, Ju

    2016-01-01

    Efficient mechanical energy harvesters enable various wearable devices and auxiliary energy supply. Here we report a novel class of mechanical energy harvesters via stress-voltage coupling in electrochemically alloyed electrodes. The device consists of two identical Li-alloyed Si as electrodes, separated by electrolyte-soaked polymer membranes. Bending-induced asymmetric stresses generate chemical potential difference, driving lithium ion flux from the compressed to the tensed electrode to generate electrical current. Removing the bending reverses ion flux and electrical current. Our thermodynamic analysis reveals that the ideal energy-harvesting efficiency of this device is dictated by the Poisson's ratio of the electrodes. For the thin-film-based energy harvester used in this study, the device has achieved a generating capacity of 15%. The device demonstrates a practical use of stress-composition-voltage coupling in electrochemically active alloys to harvest low-grade mechanical energies from various low-frequency motions, such as everyday human activities. PMID:26733282

  13. Electrochemically driven mechanical energy harvesting

    Science.gov (United States)

    Kim, Sangtae; Choi, Soon Ju; Zhao, Kejie; Yang, Hui; Gobbi, Giorgia; Zhang, Sulin; Li, Ju

    2016-01-01

    Efficient mechanical energy harvesters enable various wearable devices and auxiliary energy supply. Here we report a novel class of mechanical energy harvesters via stress-voltage coupling in electrochemically alloyed electrodes. The device consists of two identical Li-alloyed Si as electrodes, separated by electrolyte-soaked polymer membranes. Bending-induced asymmetric stresses generate chemical potential difference, driving lithium ion flux from the compressed to the tensed electrode to generate electrical current. Removing the bending reverses ion flux and electrical current. Our thermodynamic analysis reveals that the ideal energy-harvesting efficiency of this device is dictated by the Poisson's ratio of the electrodes. For the thin-film-based energy harvester used in this study, the device has achieved a generating capacity of 15%. The device demonstrates a practical use of stress-composition-voltage coupling in electrochemically active alloys to harvest low-grade mechanical energies from various low-frequency motions, such as everyday human activities.

  14. 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...

  15. 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.

  16. 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

  17. Piezoelectric Energy Harvesting From Flutter

    OpenAIRE

    Norouzi, Soroush

    2012-01-01

    With the increasing need for alternative sources of energy, a great deal of attention is drawn to harvesting energy from ambient vibration. These vibrations may be caused by fluid forces acting upon a structure. When a flexible structure is subject to a fluid flow, it loses stability at a certain flow velocity and starts to vibrate. This self-induced motion is called flutter where energy is continuously transferred from the fluid to the structure. In this study a piezoelectric film sensor is ...

  18. Nonlinear piezomagnetoelastic harvester array for broadband energy harvesting

    Science.gov (United States)

    Upadrashta, Deepesh; Yang, Yaowen

    2016-08-01

    This article proposes an array of nonlinear piezomagnetoelastic energy harvesters (NPEHs) for scavenging electrical energy from broadband vibrations with low amplitudes (parallel connections between the individual harvesters using standard AC/DC interface circuits is also investigated and compared with its linear counterpart.

  19. 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.

  20. 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....

  1. Energy-harvested Lightweight Cryptosystems

    OpenAIRE

    Mane, Deepak Hanamant

    2014-01-01

    The Internet of Things will include many resource-constrained lightweight wireless sensing devices, hungry for energy, bandwidth and compute cycles. The sheer amount of devices involved will require new solutions to handle issues such as identification and power provisioning. First, to simplify identity management, device identification is moving from symmetric-key solutions to public-key solutions. Second, to avoid the endless swapping of batteries, passively-powered energy harvesting soluti...

  2. Electrostatic Conversion for Vibration Energy Harvesting

    OpenAIRE

    Boisseau, S.; Despesse, G.; Seddik, B. Ahmed

    2012-01-01

    Comment: This is an author-created, un-copyedited version of a chapter accepted for publication in Small-Scale Energy Harvesting, Intech. The definitive version is available online at: http://dx.doi.org/10.5772/51360 Please cite as: S. Boisseau, G. Despesse and B. Ahmed Seddik, Electrostatic Conversion for Vibration Energy Harvesting, Small-Scale Energy Harvesting, Intech, 2012

  3. Principles of thermoacoustic energy harvesting

    Science.gov (United States)

    Avent, A. W.; Bowen, C. R.

    2015-11-01

    Thermoacoustics exploit a temperature gradient to produce powerful acoustic pressure waves. The technology has a key role to play in energy harvesting systems. A time-line in the development of thermoacoustics is presented from its earliest recorded example in glass blowing through to the development of the Sondhauss and Rijke tubes to Stirling engines and pulse-tube cryo-cooling. The review sets the current literature in context, identifies key publications and promising areas of research. The fundamental principles of thermoacoustic phenomena are explained; design challenges and factors influencing efficiency are explored. Thermoacoustic processes involve complex multi-physical coupling and transient, highly non-linear relationships which are computationally expensive to model; appropriate numerical modelling techniques and options for analyses are presented. Potential methods of harvesting the energy in the acoustic waves are also examined.

  4. 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.

  5. Energy-Harvesting Performances of Two Tandem Piezoelectric Energy Harvesters with Cylinders in Water

    Directory of Open Access Journals (Sweden)

    Xiaobiao Shan

    2016-08-01

    Full Text Available This paper presents a new energy-harvesting system with two identical piezoelectric energy harvesters in a tandem configuration. Each harvester consists of a piezoelectric beam and a circular cylinder. Experiments are performed to investigate the energy-harvesting performances of this system in water. It can be found that their energy-harvesting performances are all different from that of the single harvester (without an upstream or downstream harvester. The experimental results show that the water speed and the spacing ratio have significant effects on the energy-harvesting performances of the two tandem harvesters. The output power of the upstream harvester first increases, and then decreases with the water speed increasing. The maximum output power of 167.8 μW is achieved at the water speed of 0.306 m/s and the spacing ratio (L/D of 2.5. Increasing the water speed results in an increase in the energy performance of the downstream harvester. Compared with the single harvester, the performance of the downstream harvester is weakened in the low water speed range, but enhanced in the higher water speed range. Further, the output power of 533 μW is obtained by the downstream harvester at the water speed of 0.412 m/s and the spacing ratio of 1.7, which is 29 times more than that of the single harvester. The results indicate the superiority of the two tandem harvesters in energy-harvesting performance.

  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...... is achieved by placing the cantilever in a magnetic field induced by either one or two magnets located oppositely of the cantilever. The attraction force created by the magnetic field and iron foils introduces a mechanical force in opposite direction of the cantilevers restoring force causing a spring...

  7. 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.

  8. 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...

  9. Vibration energy harvester optimization using artificial intelligence

    Science.gov (United States)

    Hadas, Z.; Ondrusek, C.; Kurfurst, J.; Singule, V.

    2011-06-01

    This paper deals with an optimization study of a vibration energy harvester. This harvester can be used as autonomous source of electrical energy for remote or wireless applications, which are placed in environment excited by ambient mechanical vibrations. The ambient energy of vibrations is usually on very low level but the harvester can be used as alternative source of energy for electronic devices with an expected low level of power consumption of several mW. The optimized design of the vibration energy harvester was based on previous development and the sensitivity of harvester design was improved for effective harvesting from mechanical vibrations in aeronautic applications. The vibration energy harvester is a mechatronic system which generates electrical energy from ambient vibrations due to precision tuning up generator parameters. The optimization study for maximization of harvested power or minimization of volume and weight are the main goals of our development. The optimization study of such complex device is complicated therefore artificial intelligence methods can be used for tuning up optimal harvester parameters.

  10. Solutions for Indoor Light Energy Harvesting

    OpenAIRE

    Vignati, Stefano

    2012-01-01

    Energy harvesting (EH) was born few decades ago and evolved during the years, however only recently has found more applications thanks to the advent of wireless sensor networks and the developments in microchips technology. This thesis investigates energy harvesting potentialities, in particular those related to solar harvesting in indoor applications. Some of the most common challenges are discussed such as: the best maximum power point tracking (MPPT) algorithm for indoor systems; or the ef...

  11. Energy Harvesting from Hydraulic and Vibration Sources

    OpenAIRE

    Mohammad pour, Nima

    2014-01-01

    This doctoral thesis, is divided in two main parts. The former is about load optimisation for a hydraulic energy harvester while the latter focuses on the design and fabrication of piezoelectric energy harvesters for the single supply pre-biasing circuit. An abstract for each part is reported below: � Part I: The hydraulic power available in water pipes is usually wasted while it could be harvested and used to supply low power systems. To address this shortcoming, this study presents how load...

  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. Adaptive learning algorithms for vibration energy harvesting

    International Nuclear Information System (INIS)

    By scavenging energy from their local environment, portable electronic devices such as MEMS devices, mobile phones, radios and wireless sensors can achieve greater run times with potentially lower weight. Vibration energy harvesting is one such approach where energy from parasitic vibrations can be converted into electrical energy through the use of piezoelectric and electromagnetic transducers. Parasitic vibrations come from a range of sources such as human movement, wind, seismic forces and traffic. Existing approaches to vibration energy harvesting typically utilize a rectifier circuit, which is tuned to the resonant frequency of the harvesting structure and the dominant frequency of vibration. We have developed a novel approach to vibration energy harvesting, including adaptation to non-periodic vibrations so as to extract the maximum amount of vibration energy available. Experimental results of an experimental apparatus using an off-the-shelf transducer (i.e. speaker coil) show mechanical vibration to electrical energy conversion efficiencies of 27–34%

  15. 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.

  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. 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.

  18. Investigation of RF Signal Energy Harvesting

    Directory of Open Access Journals (Sweden)

    Soudeh Heydari Nasab

    2010-01-01

    Full Text Available The potential utilization of RF signals for DC power is experimentally investigated. The aim of the work is to investigate the levels of power that can be harvested from the air and processed to achieve levels of energy that are sufficient to charge up low-power electronic circuits. The work presented shows field measurements from two selected regions: an urbanized hence signal congested area and a less populated one. An RF harvesting system has been specifically designed, built, and shown to successfully pick up enough energy to power up circuits. The work concludes that while RF harvesting was successful under certain conditions, however, it required the support of other energy harvesting techniques to replace a battery. Efficiency considerations have, hence, placed emphasis on comparing the developed harvester to other systems.

  19. 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

  20. 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

  1. 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

  2. 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...

  3. 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

  4. 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

  5. Internal resonance for nonlinear vibration energy harvesting

    Science.gov (United States)

    Cao, D. X.; Leadenham, S.; Erturk, A.

    2015-11-01

    The transformation of waste vibration energy into low-power electricity has been heavily researched over the last decade to enable self-sustained wireless electronic components. Monostable and bistable nonlinear oscillators have been explored by several research groups in an effort to enhance the frequency bandwidth of operation. Linear two-degree-of-freedom (2-DOF) configurations as well as the combination of a nonlinear single-DOF harvester with a linear oscillator to constitute a nonlinear 2-DOF harvester have also been explored to develop broadband energy harvesters. In the present work, the concept of nonlinear internal resonance in a continuous frame structure is explored for broadband energy harvesting. The L-shaped beam-mass structure with quadratic nonlinearity was formerly studied in the nonlinear dynamics literature to demonstrate modal energy exchange and the saturation phenomenon when carefully tuned for two-to-one internal resonance. In the current effort, piezoelectric coupling and an electrical load are introduced, and electromechanical equations of the L-shaped energy harvester are employed to explore primary resonance behaviors around the first and the second linear natural frequencies for bandwidth enhancement. Simulations using approximate analytical frequency response equations as well as numerical solutions reveal significant bandwidth enhancement as compared to a typical linear 2-DOF counterpart. Vibration and voltage responses are explored, and the effects of various system parameters on the overall dynamics of the internal resonance-based energy harvesting system are reported.

  6. 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.

  7. Electromagnetic ferrofluid-based energy harvester

    Energy Technology Data Exchange (ETDEWEB)

    Bibo, A.; Masana, R.; King, A.; Li, G. [Nonlinear Vibrations and Energy Harvesting Laboratory (NOVEHL), Department of Mechanical Engineering, Clemson University, Clemson, SC 29634 (United States); Daqaq, M.F., E-mail: mdaqaq@clemson.edu [Nonlinear Vibrations and Energy Harvesting Laboratory (NOVEHL), Department of Mechanical Engineering, Clemson University, Clemson, SC 29634 (United States)

    2012-06-25

    This Letter investigates the use of ferrofluids for vibratory energy harvesting. In particular, an electromagnetic micro-power generator which utilizes the sloshing of a ferrofluid column in a seismically-excited tank is proposed to transform mechanical motions directly into electricity. Unlike traditional electromagnetic generators that implement a solid magnet, ferrofluids can easily conform to different shapes and respond to very small acceleration levels offering an untapped opportunity to design scalable energy harvesters. The feasibility of the proposed concept is demonstrated and its efficacy is discussed through several experimental studies. -- Highlights: ► A ferrofluid-based electromagnetic energy harvester is proposed and tested. Conformability of fluids offers unique capabilities to design scalable harvesters. ► Power is sensitive to changes in the fluid surface area and external magnetization. ► Device generates 1 microwatt of output power at a base acceleration of 3 m/s{sup 2}.

  8. 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 (easy to fabricate. Several important steps have been taken by Wang's group to develop TENG technology for 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. PMID:27408982

  9. Impedance matching for broadband piezoelectric energy harvesting

    Science.gov (United States)

    Hagedorn, F.; Leicht, J.; Sanchez, D.; Hehn, T.; Manoli, Y.

    2013-12-01

    This paper presents a system design for broadband piezoelectric energy harvesting by means of impedance matching. An inductive load impedance is emulated by controlling the output current of the piezoelectric harvester with a bipolar boost converter. The reference current is derived from the low pass filtered voltage measured at the harvester terminals. In order to maximize the harvested power especially for nonresonant frequencies the filter parameters are adjusted by a simple optimization algorithm. However the amount of harvested power is limited by the efficiency of the bipolar boost converter. Therefore an additional switch in the bipolar boost converter is proposed to reduce the capacitive switching losses. The proposed system is simulated using numerical parameters of available discrete components. Using the additional switch, the harvested power is increased by 20%. The proposed system constantly harvests 80% of the theoretically available power over frequency. The usable frequency range of ±4Hz around the resonance frequency of the piezoelectric harvester is mainly limited due to the boost converter topology. This comparison does not include the power dissipation of the control circuit.

  10. Enhanced energy harvesting in commercial ferroelectric materials

    Science.gov (United States)

    Patel, Satyanarayan; Chauhan, Aditya; Vaish, Rahul

    2014-04-01

    Ferroelectric materials are used in a number of applications ranging from simple sensors and actuators to ferroelectric random access memories (FRAMs), transducers, health monitoring system and microelectronics. The multiphysical coupling ability possessed by these materials has been established to be useful for energy harvesting applications. However, conventional energy harvesting techniques employing ferroelectric materials possess low energy density. This has prevented the successful commercialization of ferroelectric based energy harvesting systems. In this context, the present study aims at proposing a novel approach for enhanced energy harvesting using commercially available ferroelectric materials. This technique was simulated to be used for two commercially available piezoelectric materials namely PKI-552 and APCI-840, soft and hard lead-zirconate-titanate (PZT) pervoskite ceramics, respectively. It was observed that a maximum energy density of 348 kJm-3cycle-1 can be obtained for cycle parameters of (0-1 ton compressive stress and 1-25 kV.cm-1 electric field) using APCI-840. The reported energy density is several hundred times larger than the maximum energy density reported in the literature for vibration harvesting systems.

  11. 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.

  12. 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

  13. 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.

  14. 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

  15. Energy harvesting from hydraulic pressure fluctuations

    Science.gov (United States)

    Cunefare, K. A.; Skow, E. A.; Erturk, A.; Savor, J.; Verma, N.; Cacan, M. R.

    2013-02-01

    State-of-the-art hydraulic hose and piping systems employ integral sensor nodes for structural health monitoring to avoid catastrophic failures. Energy harvesting in hydraulic systems could enable self-powered wireless sensor nodes for applications such as energy-autonomous structural health monitoring and prognosis. Hydraulic systems inherently have a high energy intensity associated with the mean pressure and flow. Accompanying the mean pressure is the dynamic pressure ripple, which is caused by the action of pumps and actuators. Pressure ripple is a deterministic source with a periodic time-domain behavior conducive to energy harvesting. An energy harvester prototype was designed for generating low-power electricity from pressure ripples. The prototype employed an axially-poled off-the-shelf piezoelectric stack. A housing isolated the stack from the hydraulic fluid while maintaining a mechanical coupling allowing for dynamic-pressure-induced deflection of the stack. The prototype exhibited an off-resonance energy harvesting problem since the fundamental resonance of the piezoelectric stack was much higher than the frequency content of the pressure ripple. The prototype was designed to provide a suitable power output for powering sensors with a maximum output of 1.2 mW. This work also presents electromechanical model simulations and experimental characterization of the piezoelectric power output from the pressure ripple in terms of the force transmitted into the harvester.

  16. Energy harvesting devices, systems, and related methods

    Energy Technology Data Exchange (ETDEWEB)

    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.

  17. 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.

  18. A self-adaptive energy harvesting system

    Science.gov (United States)

    Hoffmann, D.; Willmann, A.; Hehn, T.; Folkmer, B.; Manoli, Y.

    2016-03-01

    This paper reports on a self-adaptive energy harvesting system, which is able to adapt its eigenfrequency to the operating conditions of power units. The power required for frequency tuning is delivered by the energy harvester itself. The tuning mechanism is based on a magnetic concept and incorporates a circular tuning magnet and a coupling magnet. In this manner, both coupling modes (attractive and repulsive) can be utilized for tuning the eigenfrequency of the energy harvester. The tuning range and its center frequency can be tailored to the application by careful design of the spring stiffness and the gap between tuning magnet and coupling magnet. Experimental results demonstrate that, in contrast to a conventional non-tunable vibration energy harvester, the net power can be significantly increased if a self-adaptive system is utilized, although additional power is required for regular adjustments of the eigenfrequency. The outcome confirms that active tuning is a real and practical option to extend the operational frequency range and to increase the net power of a conventional vibration energy harvester.

  19. Cantilever-based electret energy harvesters

    International Nuclear Information System (INIS)

    Integration of structures and functions has permitted the electricity consumption of sensors, actuators and electronic devices to be reduced. Therefore, it is now possible to imagine low-consumption devices able to harvest energy from their surrounding environment. One way to proceed is to develop converters able to turn mechanical energy, such as vibrations, into electricity: this paper focuses on electrostatic converters using electrets. We develop an accurate analytical model of a simple but efficient cantilever-based electret energy harvester. We prove that with vibrations of 0.1g (∼1 m s−2), it is theoretically possible to harvest up to 30 µW per gram of mobile mass. This power corresponds to the maximum output power of a resonant energy harvester according to the model of William and Yates. Simulation results are validated by experimental measurements, raising at the same time the large impact of parasitic capacitances on the output power. Therefore, we 'only' managed to harvest 10 µW per gram of mobile mass, but according to our factor of merit, this is among the best results so far achieved

  20. Thermal energy harvesting plasmonic based chemical sensors.

    Science.gov (United States)

    Karker, Nicholas; Dharmalingam, Gnanaprakash; Carpenter, Michael A

    2014-10-28

    Detection of gases such as H2, CO, and NO2 at 500 °C or greater requires materials with thermal stability and reliability. One of the major barriers toward integration of plasmonic-based chemical sensors is the requirement of multiple components such as light sources and spectrometers. In this work, plasmonic sensing results are presented where thermal energy is harvested using lithographically patterned Au nanorods, replacing the need for an external incident light source. Gas sensing results using the harvested thermal energy are in good agreement with sensing experiments, which used an external incident light source. Principal Component Analysis (PCA) was used to reduce the wavelength parameter space from 665 variables down to 4 variables with similar levels of demonstrated selectivity. The combination of a plasmonic-based energy harvesting sensing paradigm with PCA analysis offers a novel path toward simplification and integration of plasmonic-based sensing methods. PMID:25280004

  1. Electromagnetic ferrofluid-based energy harvester

    Science.gov (United States)

    Bibo, A.; Masana, R.; King, A.; Li, G.; Daqaq, M. F.

    2012-06-01

    This Letter investigates the use of ferrofluids for vibratory energy harvesting. In particular, an electromagnetic micro-power generator which utilizes the sloshing of a ferrofluid column in a seismically-excited tank is proposed to transform mechanical motions directly into electricity. Unlike traditional electromagnetic generators that implement a solid magnet, ferrofluids can easily conform to different shapes and respond to very small acceleration levels offering an untapped opportunity to design scalable energy harvesters. The feasibility of the proposed concept is demonstrated and its efficacy is discussed through several experimental studies.

  2. An Equivalent Circuit Model for Electrostatic Energy Harvester utilized Energy Harvesting System

    International Nuclear Information System (INIS)

    In this study, we report an equivalent circuit model of an electrostatic energy harvester for a SPICE circuit simulator. In order to simulate a harvesting system, the output power of the device is calculated in the simulator. The capacitance between the electrodes is obtained by FEM analysis by taking the fringing effect into account and the result is applied to a sub-circuit model for the simulator. Mechanical vibrations are converted into electricity by an equivalent circuit model of a mass-spring structure and an electrostatic energy harvester. The simulated output power and output waveform correspond with the measurement results of our electrostatic energy harvester. We also simulate the operation of a harvesting system connected with a power management IC

  3. Piezoelectric energy harvesting from raised crosswalk devices

    Science.gov (United States)

    Ticali, Dario; Denaro, Mario; Barracco, Alessandro; Guerrieri, Marco

    2015-03-01

    This paper presents the main characteristics of an experimental energy harvesting device that can be used to recover energy from the vehicular and pedestrian traffic. The use of a piezoelectric bender devices leads to a innovative approach to Henergy Harvesting. The study focuses on the definition and specification of a mechanical configuration able to transfer the vibration from the main box to the piezoelectric transducer. The piezoelectric devices tested is the commonly used monolithic piezoceramic material lead-zirconate-titanate (PZT). The experimental results estimate the efficiency of this device tested and identify the feasibility of their use in real world applications. The results presented in this paper show the potential of piezoelectric materials for use in power harvesting applications.

  4. Subwavelength resonant antennas enhancing electromagnetic energy harvesting

    Science.gov (United States)

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

    2016-04-01

    In this work, an electromagnetic energy harvester operating at microwave frequencies is designed based on a cut- wire metasurface. This metamaterial is known to contain a quasistatic electric dipole resonator leading to a strong resonant electric response when illuminated by electromagnetic fields.1 Starting from an equivalent electrical circuit, we analytically design the parameters of the system to tune the resonance frequency of the harvester at the desired frequency band. Subsequently, we compare these results with numerical simulations, which have been obtained using finite elements numerical simulations. Finally, we optimize the design by investigating the best arrangement for energy harvesting by coupling in parallel and in series many single layers of cut-wire metasurfaces. We also discuss the implementation of different geometries and sizes of the cut-wire metasurface for achieving different center frequencies and bandwidths.

  5. Piezoelectric monolayers as nonlinear energy harvesters.

    Science.gov (United States)

    López-Suárez, Miquel; Pruneda, Miguel; Abadal, Gabriel; Rurali, Riccardo

    2014-05-01

    We study the dynamics of h-BN monolayers by first performing ab-initio calculations of the deformation potential energy and then solving numerically a Langevine-type equation to explore their use in nonlinear vibration energy harvesting devices. An applied compressive strain is used to drive the system into a nonlinear bistable regime, where quasi-harmonic vibrations are combined with low-frequency swings between the minima of a double-well potential. Due to its intrinsic piezoelectric response, the nonlinear mechanical harvester naturally provides an electrical power that is readily available or can be stored by simply contacting the monolayer at its ends. Engineering the induced nonlinearity, a 20 nm2 device is predicted to harvest an electrical power of up to 0.18 pW for a noisy vibration of 5 pN. PMID:24722065

  6. 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.

  7. Broadband magnetic levitation-based nonlinear energy harvester

    Science.gov (United States)

    Nammari, Abdullah; Doughty, Seth; Savage, Dustin; Weiss, Leland; Jaganathan, Arun; Bardaweel, Hamzeh

    2016-05-01

    In this work, development of a broadband nonlinear electromagnetic energy harvester is described. The energy harvester consists of a casing housing stationary magnets, a levitated magnet, oblique mechanical springs, and a coil. Magnetic and oblique springs introduce nonlinear behavior into the energy harvester. A mathematical model of the proposed device is developed and validated. The results show good agreement between model and experiment. The significance of adding oblique mechanical springs to the energy harvester design is investigated using the model simulation. The results from the model suggest that adding oblique springs to the energy harvester will improve the performance and increase the frequency bandwidth and amplitude response of the energy harvester.

  8. Conductive Fabric-Based Stretchable Hybridized Nanogenerator for Scavenging Biomechanical Energy.

    Science.gov (United States)

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

    2016-04-26

    We demonstrate a stretchable hybridized nanogenerator based on a highly conductive fabric of glass fibers/silver nanowires/polydimethylsiloxane. Including a triboelectric nanogenerator and an electromagnetic generator, the hybridized nanogenerator can deliver output voltage/current signals from stretchable movements by both triboelectrification and electromagnetic induction, maximizing the efficiency of energy scavenging from one motion. Compared to the individual energy-harvesting units, the hybridized nanogenerator has a better charging performance, where a 47 μF capacitor can be charged to 2.8 V in only 16 s. The hybridized nanogenerator can be integrated with a bus grip for scavenging wasted biomechanical energy from human body movements to solve the power source issue of some electric devices in the pure electric bus. PMID:26989809

  9. 3D Energy Harvester Evaluation

    OpenAIRE

    V. Janicek; M. Husak

    2013-01-01

    This paper discusses the characterization and evaluation of an MEMS based electrostatic generator, a part of the power supply unit of the self-powered microsystem[1,2,3]. The designed generator is based on electrostatic converter and uses the principle of conversion of non-electric energy into electrical energy by periodical modification of gap between electrodes of a capacitor [4]. The structure is designed and modeled as three-dimensional silicon based MEMS. Innovative approach involving th...

  10. 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.

  11. 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.

  12. Thermoelectric Energy Harvesting Via Piezoelectric Material

    OpenAIRE

    Li, Lijie

    2015-01-01

    Thermoelectric energy harvesters can have a much higher conversion efficiency by implementing quantum dots/wells between the high temperature region and the low temperature region. However they still suffer a limitation of the maximum output power, represented by the maximum $\\Delta E$ (maximum energy gap of two quantum dots/wells layers). In this work, we use the piezoelectric material in the high temperature region, which has conceptually addressed the problem of the maximum power limitatio...

  13. 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.

  14. 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.

  15. 3D Energy Harvester Evaluation

    Directory of Open Access Journals (Sweden)

    V. Janicek

    2013-04-01

    Full Text Available This paper discusses the characterization and evaluation of an MEMS based electrostatic generator, a part of the power supply unit of the self-powered microsystem[1,2,3]. The designed generator is based on electrostatic converter and uses the principle of conversion of non-electric energy into electrical energy by periodical modification of gap between electrodes of a capacitor [4]. The structure is designed and modeled as three-dimensional silicon based MEMS. Innovative approach involving the achievement of very low resonant frequency of the structure (about 100Hz by usage of modified long cantilever spring design, minimum area of the chip, 3D work mode, the ability to be tuned to reach desired parameters, proves promising directions of possible further development.

  16. Piezoelectric energy harvesting from hybrid vibrations

    Science.gov (United States)

    Yan, Zhimiao; Abdelkefi, Abdessattar; Hajj, Muhammad R.

    2014-02-01

    The concept of harvesting energy from ambient and galloping vibrations of a bluff body with a triangular cross-section geometry is investigated. A piezoelectric transducer is attached to the transverse degree of freedom of the body in order to convert these vibrations to electrical energy. A coupled nonlinear distributed-parameter model is developed that takes into consideration the galloping force and moment nonlinearities and the base excitation effects. The aerodynamic loads are modeled using the quasi-steady approximation. Linear analysis is performed to determine the effects of the electrical load resistance and wind speed on the global damping and frequency of the harvester as well as on the onset of instability. Then, nonlinear analysis is performed to investigate the impact of the base acceleration, wind speed, and electrical load resistance on the performance of the harvester and the associated nonlinear phenomena that take place. The results show that, depending on the interaction between the base and galloping excitations, and the considered values of the wind speed, base acceleration, and electrical load resistance, different nonlinear phenomena arise while others disappear. Short- and open-circuit configurations for different wind speeds and base accelerations are assessed. The results show that the maximum levels of harvested power are accompanied by a minimum transverse displacement when varying the electrical load resistance.

  17. Energy harvesting in high voltage measuring techniques

    Science.gov (United States)

    Żyłka, Pawel; Doliński, Marcin

    2016-02-01

    The paper discusses selected problems related to application of energy harvesting (that is, generating electricity from surplus energy present in the environment) to supply autonomous ultra-low-power measurement systems applicable in high voltage engineering. As a practical example of such implementation a laboratory model of a remote temperature sensor is presented, which is self-powered by heat generated in a current-carrying busbar in HV- switchgear. Presented system exploits a thermoelectric harvester based on a passively cooled Peltier module supplying micro-power low-voltage dc-dc converter driving energy-efficient temperature sensor, microcontroller and a fibre-optic transmitter. Performance of the model in laboratory simulated conditions are presented and discussed.

  18. 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.

  19. 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.

  20. 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.

  1. 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...

  2. Human Motion Energy Harvesting for AAL Applications

    International Nuclear Information System (INIS)

    Research and development into the topic of ambient assisted living has led to an increasing range of devices that facilitate a person's life. The issue of the power supply of these modern mobile systems however has not been solved satisfactorily yet. In this paper a flat inductive multi-coil harvester for integration into the shoe sole is presented. The device is designed for ambient assisted living (AAL) applications and particularly to power a self-lacing shoe. The harvester exploits the horizontal swing motion of the foot to generate energy. Stacks of opposing magnets move through a number of equally spaced coils to induce a voltage. The requirement of a flat structure which can be integrated into the shoe sole is met by a reduced form factor of the magnet stack. In order to exploit the full width of the shoe sole, supporting structures are used to parallelize the harvester and therefore increase the number of active elements, i.e. magnets and coils. The development and characterization of different harvester variations is presented with the best tested design generating an average power of up to 2.14 mW at a compact device size of 75 × 41.5 × 15 mm3 including housing

  3. Energy Harvesting System for aerospace application

    OpenAIRE

    Ccorimanya Becerra, Hernan Manuel

    2013-01-01

    [ANGLÈS] The Energy Harvesting is really interesting concept nowadays because it consists in get energy from the environment that is already there. Nowadays application and commons such as nodes of a wireless network self-powered, the flexibility to locate them give an interesting advantages to allocate the network in strategic points or even to difficult places. Alternatively, it can be set out from this energy source a sub-system inside the other sub-system more big, that can be self-powere...

  4. 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.

  5. 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.

  6. 2-Dimensional Personal Motion Energy Harvester for Low Power Electronics

    OpenAIRE

    Gutierrez, Manuel; Scott, Sean; Peroulis, Dimitrios

    2013-01-01

    In a lab, it becomes crucial to have a way to monitor that lab workers aren’t exposed to too much radiation. Such a device that detects this should have an energy harvester so that batteries aren’t required. The need for an energy harvester that generates power from a user’s movements in 2 dimensions is needed. This energy harvester is needed to power a radiation monitor. An energy harvester that generates power based off movements in 2 dimensions was developed. The energy harvester was creat...

  7. Nonlinearities in energy-harvesting media

    Science.gov (United States)

    Andrews, David L.; Jenkins, Robert D.

    2001-07-01

    Both in natural photosynthetic systems and also their molecularly engineered mimics, energy is generally transferred to the sites of its chemical storage from other sites of primary optical excitation. This migration process generally entails a number of steps, frequently involving intermediary chromophore units, with each step characterised by high efficiency and rapidity. Energy thereby accrues at reaction centres where its chemical storage occurs. At high levels of irradiation, energy harvesting material can exhibit novel forms of optical nonlinearity. Such behaviour is associated with the direct pooling of excitation energy, enabling secondary acceptors to undergo transitions to states whose energy equals that of two or more input photons, subject to decay losses. Observations of this kind have now been made on a variety of materials, ranging from photoactive dyes, through fullerene derivatives, to lanthanide doped crystals. Recently developed theory has established the underlying principles and links between the modes of operation of these systems. Key factors include the chromophore layout and geometry, electronic structure and optical selection rules. Mesoscopic symmetry, especially in photosynthetic pigment arrays and also in their dendrimeric mimics, is here linked to the transient establishment of excitons. The involvement of excitons in energy harvesting is nonetheless substantially compromised by local disorder. The interplay of these factors in photoactive materials design is discussed in the context of new materials for operation with intense laser light.

  8. Ferrofluid based micro-electrical energy harvesting

    Science.gov (United States)

    Purohit, Viswas; Mazumder, Baishakhi; Jena, Grishma; Mishra, Madhusha; Materials Department, University of California, Santa Barbara, CA93106 Collaboration

    2013-03-01

    Innovations in energy harvesting have seen a quantum leap in the last decade. With the introduction of low energy devices in the market, micro energy harvesting units are being explored with much vigor. One of the recent areas of micro energy scavenging is the exploitation of existing vibrational energy and the use of various mechanical motions for the same, useful for low power consumption devices. Ferrofluids are liquids containing magnetic materials having nano-scale permanent magnetic dipoles. The present work explores the possibility of the use of this property for generation of electricity. Since the power generation is through a liquid material, it can take any shape as well as response to small acceleration levels. In this work, an electromagnet-based micropower generator is proposed to utilize the sloshing of the ferrofluid within a controlled chamber which moves to different low frequencies. As compared to permanent magnet units researched previously, ferrofluids can be placed in the smallest of containers of different shapes, thereby giving an output in response to the slightest change in motion. Mechanical motion from 1- 20 Hz was able to give an output voltage in mV's. In this paper, the efficiency and feasibility of such a system is demonstrated.

  9. Harvesting Energy from Vibrations of the Underlying Structure

    DEFF Research Database (Denmark)

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

    2013-01-01

    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...... 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...

  10. 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.

  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. Models for 31-Mode PVDF Energy Harvester for Wearable Applications

    Directory of Open Access Journals (Sweden)

    Jingjing Zhao

    2014-01-01

    Full Text Available 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%.

  13. 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%. PMID:25114981

  14. 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.

  15. 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.

  16. Flexible Electret Energy Harvester with Copper Mesh Electrodes

    International Nuclear Information System (INIS)

    Flexible energy harvesters are desired in biomedical applications since human motion is often complicated and aperiodic. However, most demonstrated flexible energy harvesters employ piezoelectric materials which are not biocompatible. Therefore we propose a PDMS-based flexible energy harvester with Parylene-C electret suitable for biomedical applications. To address the reliability issues of sputtered metal electrodes, we use copper mesh electrodes to improve the reliability. The proposed flexible harvester was fabricated and characterized. The measured power of the proposed harvester was 3.33 pW in the compression tests at 20 Hz and 8.5 nW in the finger bending tests at 2 Hz

  17. 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.

  18. 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.

  19. 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.

  20. 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...

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

    OpenAIRE

    Jingjing Zhao; Zheng You

    2014-01-01

    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 wit...

  2. 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.

  3. 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.).

  4. Flexible electret energy harvesters with parylene electret on PDMS substrates

    Science.gov (United States)

    Chiu, Yi; Wu, Shih-Hsien

    2013-12-01

    Currently, most vibrational energy harvesters have rigid and resonant structures to harvest energy from periodic motions in specific directions. However, in some situations the motion is random and aperiodic; or the targeted energy source is the strain energy in deformation, rather than the kinetic energy in vibration. Therefore we propose and demonstrate a PDMS-based flexible energy harvester with parylene-C electret that can be attached to any deformable surfaces to harvest the stain energy caused by external deformation. The proposed flexible harvester was fabricated and characterized. The measured power at 20 Hz is 0.18 μW and 82 nW in the compression and bending modes, respectively. Such a harvester has the potential for wearable and implantable electronics applications.

  5. 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…

  6. Fluidic energy harvesting beams in grid turbulence

    Science.gov (United States)

    Danesh-Yazdi, A. H.; Goushcha, O.; Elvin, N.; Andreopoulos, Y.

    2015-08-01

    Much of the recent research involving fluidic energy harvesters based on piezoelectricity has focused on excitation through vortex-induced vibration while turbulence-induced excitation has attracted very little attention, and virtually no previous work exists on excitation due to grid-generated turbulence. The present experiments involve placing several piezoelectric cantilever beams of various dimensions and properties in flows where turbulence is generated by passive, active, or semi-passive grids, the latter having a novel design that significantly improves turbulence generation compared to the passive grid and is much less complex than the active grid. We experimentally show for the first time that the average power harvested by a piezoelectric cantilever beam placed in decaying isotropic, homogeneous turbulence depends on mean velocity, velocity and length scales of turbulence as well as the electromechanical properties of the beam. The output power can be modeled as a power law with respect to the distance of the beam from the grid. Furthermore, we show that the rate of decay of this power law closely follows the rate of decay of the turbulent kinetic energy. We also introduce a forcing function used to model approximately the turbulent eddies moving over the cantilever beam and observe that the feedback from the beam motion onto the flow is virtually negligible for most of the cases considered, indicating an effectively one-way interaction for small-velocity fluctuations.

  7. 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.

  8. 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.

  9. Flexible Piezoelectric Energy Harvesting from Mouse Click Motions

    Directory of Open Access Journals (Sweden)

    Youngsu Cha

    2016-07-01

    Full Text Available 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.

  10. Flexible Piezoelectric Energy Harvesting from Mouse Click Motions.

    Science.gov (United States)

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

    2016-01-01

    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. PMID:27399705

  11. Flexible Piezoelectric Energy Harvesting from Mouse Click Motions

    Science.gov (United States)

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

    2016-01-01

    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. PMID:27399705

  12. Energy harvesting with piezoelectric applied on shoes

    Science.gov (United States)

    Camilloni, Enrico; Carloni, Mirko; Giammarini, Marco; Conti, Massimo

    2013-05-01

    In the last few years the continuous demand of energy saving has brought continuous research on low-power devices, energy storage and new sources of energy. Energy harvesting is an interesting solution that captures the energy from the environment that would otherwise be wasted. This work presents an electric-mechanical model of a piezoelectric transducer in a cantilever configuration. The model has been characterized measuring the acceleration and the open circuit voltage of a piezoelectric cantilever subjected to a sinusoidal force with different values frequency and subject to an impulsive force. The model has been used to identify the optimal position in which the piezoelectric cantilever has to be placed on a shoe in order to obtain the maximum energy while walking or running. As a second step we designed the DC-DC converter with an hysteresis comparator. The circuit is able to give energy to switch on a microprocessor for the amount of time long enough to capture and store the information required. The complete system has been implemented, installed on a shoe and used in a 10 Km running competition.

  13. 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

    2015-04-01

    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. PMID:25476410

  14. Parametrization of ambient energy harvesters for complementary balanced electronic applications

    Science.gov (United States)

    Verbelen, Yannick; Braeken, An; Touhafi, Abdellah

    2013-05-01

    The specific technical challenges associated with the design of an ambient energy powered electronic system currently requires thorough knowledge of the environment of deployment, energy harvester characteristics and power path management. In this work, a novel flexible model for ambient energy harvesters is presented that allows decoupling of the harvester's physical principles and electrical behavior using a three dimensional function. The model can be adapted to all existing harvesters, resulting in a design methodology for generic ambient energy powered systems using the presented model. Concrete examples are included to demonstrate the versatility of the presented design in the development of electronic appliances on system level.

  15. 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 elec......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...

  16. Piezomagnetoelastic broadband energy harvester: Nonlinear modeling and characterization

    Science.gov (United States)

    Aravind Kumar, K.; Ali, S. F.; Arockiarajan, A.

    2015-11-01

    Piezomagnetoelastic energy harvesters are one among the widely explored configurations to improve the broadband characteristics of vibration energy harvesters. Such nonlinear harvesters follow a Moon beam model with two magnets at the base and one at the tip of the beam. The present article develops a geometric nonlinear mathematical model for the broadband piezomagnetoelastic energy harvester. The electromechanical coupling and the nonlinear magnetic potential equations are developed from the dimensional system parameters to describe the nonlinear dynamics exhibited by the system. The developed model is capable of characterizing the monostable, bistable and tristable operating regimes of the piezomagnetoelastic energy harvester, which are not explicit in the Duffing representation of the system. Bifurcations and attractor motions are analyzed as nonlinear functions of the distance between base magnets and the field strength of the tip magnet. The model is further used to characterize the potential wells and stable states, with due focus on the performance of the system in broadband energy harvesting.

  17. 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.

  18. Multiple cell configuration electromagnetic vibration energy harvester

    International Nuclear Information System (INIS)

    This paper reports the design of an electromagnetic vibration energy harvester that doubles the magnitude of output power generated by the prior four-bar magnet configuration. This enhancement was achieved with minor increase in volume by 23% and mass by 30%. The new 'double cell' design utilizes an additional pair of magnets to create a secondary air gap, or cell, for a second coil to vibrate within. To further reduce the dimensions of the device, two coils were attached to one common cantilever beam. These unique features lead to improvements of 66% in output power per unit volume (power density) and 27% increase in output power per unit volume and mass (specific power density), from 0.1 to 0.17 mW cm-3 and 0.41 to 0.51 mW cm-3 kg-1 respectively. Using the ANSYS multiphysics analysis, it was determined that for the double cell harvester, adding one additional pair of magnets created a small magnetic gradient between air gaps of 0.001 T which is insignificant in terms of electromagnetic damping. An analytical model was developed to optimize the magnitude of transformation factor and magnetic field gradient within the gap.

  19. Piezoelectric energy harvesting in internal fluid flow.

    Science.gov (United States)

    Lee, Hyeong Jae; Sherrit, Stewart; Tosi, Luis Phillipe; Walkemeyer, Phillip; Colonius, Tim

    2015-01-01

    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. PMID:26473879

  20. Mechanics of flexible and stretchable piezoelectrics for energy harvesting

    Science.gov (United States)

    Chen, Ying; Lu, BingWei; Ou, DaPeng; Feng, Xue

    2015-09-01

    As rapid development in wearable/implantable electronic devices benefit human life in daily health monitoring and disease treatment medically, all kinds of flexible and/or stretchable electronic devices are booming, together with which is the demanding of energy supply with similar mechanical property. Due to its ability in converting mechanical energy lying in human body into electric energy, energy harvesters based on piezoelectric materials are promising for applications in wearable/ implantable device's energy supply in a renewable, clean and life-long way. Here the mechanics of traditional piezoelectrics in energy harvesting is reviewed, including why piezoelectricity is the choice for minor energy harvesting to power the implantable/wearable electronics and how. Different kinds of up to date flexible piezoelectric devices for energy harvesting are introduced, such as nanogenerators based on ZnO and thin and conformal energy harvester based on PZT. A detailed theoretical model of the flexible thin film energy harvester based on PZT nanoribbons is summarized, together with the in vivo demonstration of energy harvesting by integrating it with swine heart. Then the initial researches on stretchable energy harvesters based on piezoelectric material in wavy or serpentine configuration are introduced as well.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. Nonlinear modeling of MEMS piezoelectric energy harvesters

    Science.gov (United States)

    Wang, Y. C.; Huang, T. W.; Shu, Y. C.; Lin, S. C.; Wu, W. J.

    2016-04-01

    This article presents the modeling of nonlinear response of micro piezoelectric energy harvesters under amplified base excitation. The micro transducer is a composite cantilever beam made of the PZT thick film deposited on the stainless-steel substrate. The model is developed based on the Euler-Bernoulli beam theory considering geometric and inertia nonlinearities, and the reduced formulation is derived based on the Hamiltonian variational principle. The harmonic balance method is used to simulate the nonlinear frequency response under various magnitudes of excitation and electric loads. The hardening type of nonlinearity is predicted and is found to be in good agreement with experiment. However, the softening response is also observed in different samples fabricated under different conditions. Such disagreement is under investigation.

  6. Review of the application of energy harvesting in buildings

    International Nuclear Information System (INIS)

    This review presents the state of the art of the application of energy harvesting in commercial and residential buildings. Electromagnetic (optical and radio frequency), kinetic, thermal and airflow-based energy sources are identified as potential energy sources within buildings and the available energy is measured in a range of buildings. Suitable energy harvesters are discussed and the available and the potential harvested energy calculated. Calculations based on these measurements, and the technical specifications of state-of-the-art harvesters, show that typical harvested powers are: (1) indoor solar cell (active area of 9 cm2, volume of 2.88 cm3): ∼300 µW from a light intensity of 1000 lx; (2) thermoelectric harvester (volume of 1.4 cm3): 6 mW from a thermal gradient of 25 °C; (3) periodic kinetic energy harvester (volume of 0.15 cm3): 2 µW from a vibration acceleration of 0.25 m s−2 at 45 Hz; (4) electromagnetic wave harvester (13 cm antenna length and conversion efficiency of 0.7): 1 µW with an RF source power of −25 dBm; and (5) airflow harvester (wind turbine blade of 6 cm diameter and generator efficiency of 0.41): 140 mW from an airflow of 8 m s−1. These results highlight the high potential of energy harvesting technology in buildings and the relative attractions of various harvester technologies. The harvested power could either be used to replace batteries or to prolong the life of rechargeable batteries for low-power (∼1 mW) electronic devices. (topical review)

  7. 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.

  8. Converting biomechanical energy into electricity by a muscle-movement-driven nanogenerator.

    Science.gov (United States)

    Yang, Rusen; Qin, Yong; Li, Cheng; Zhu, Guang; Wang, Zhong Lin

    2009-03-01

    A living species has numerous sources of mechanical energy, such as muscle stretching, arm/leg swings, walking/running, heart beats, and blood flow. We demonstrate a piezoelectric nanowire based nanogenerator that converts biomechanical energy, such as the movement of a human finger and the body motion of a live hamster (Campbell's dwarf), into electricity. A single wire generator (SWG) consists of a flexible substrate with a ZnO nanowire affixed laterally at its two ends on the substrate surface. Muscle stretching results in the back and forth stretching of the substrate and the nanowire. The piezoelectric potential created inside the wire leads to the flow of electrons in the external circuit. The output voltage has been increased by integrating multiple SWGs. A series connection of four SWGs produced an output voltage of up to approximately 0.1-0.15 V. The success of energy harvesting from a tapping finger and a running hamster reveals the potential of using the nanogenerators for scavenging low-frequency energy from regular and irregular biomotion. PMID:19203203

  9. 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.

  10. 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.

  11. 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.

  12. 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...... matching between the harvesters resonant frequency and vibration sources in the low frequency range, the thickness of the cantilever is required to be in the sub- 100 µm range not to compromise the total dimension of the harvester. Fabricating this challenging and fragile design with the cantilever...

  13. 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.

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

    OpenAIRE

    Hyeong-Kyu Lee; MinGyu Lee; Tae-Jin Lee

    2015-01-01

    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...

  15. 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.

  16. 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...

  17. Plasmonic Enhancement Mechanisms in Solar Energy Harvesting

    Science.gov (United States)

    Cushing, Scott K.

    Semiconductor photovoltaics (solar-to-electrical) and photocatalysis (solar-to-chemical) requires sunlight to be converted into excited charge carriers with sufficient lifetimes and mobility to drive a current or photoreaction. Thin semiconductor films are necessary to reduce the charge recombination and mobility losses, but thin films also limit light absorption, reducing the solar energy conversion efficiency. Further, in photocatalysis, the band edges of semiconductor must straddle the redox potentials of a photochemical reaction, reducing light absorption to half the solar spectrum in water splitting. Plasmonics transforms metal nanoparticles into antennas with resonances tuneable across the solar spectrum. If energy can be transferred from the plasmon to the semiconductor, light absorption in the semiconductor can be increased in thin films and occur at energies smaller than the band gap. This thesis investigates why, despite this potential, plasmonic solar energy harvesting techniques rarely appear in top performing solar architectures. To accomplish this goal, the possible plasmonic enhancement mechanisms for solar energy conversion were identified, isolated, and optimized by combining systematic sample design with transient absorption spectroscopy, photoelectrochemical and photocatalytic testing, and theoretical development. Specifically, metal semiconductor nanostructures were designed to modulate the plasmon's scattering, hot carrier, and near field interactions as well as remove heating and self-catalysis effects. Transient absorption spectroscopy then revealed how the structure design affected energy and charge carrier transfer between metal and semiconductor. Correlating this data with wavelength-dependent photoconversion efficiencies and theoretical developments regarding metal-semiconductor interactions identified the origin of the plasmonic enhancement. Using this methodology, it has first been proven that three plasmonic enhancement routes are

  18. 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.

  19. 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...

  20. 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, nam...

  1. 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.

  2. Plasmonic Enhancement Mechanisms in Solar Energy Harvesting

    Science.gov (United States)

    Cushing, Scott K.

    Semiconductor photovoltaics (solar-to-electrical) and photocatalysis (solar-to-chemical) requires sunlight to be converted into excited charge carriers with sufficient lifetimes and mobility to drive a current or photoreaction. Thin semiconductor films are necessary to reduce the charge recombination and mobility losses, but thin films also limit light absorption, reducing the solar energy conversion efficiency. Further, in photocatalysis, the band edges of semiconductor must straddle the redox potentials of a photochemical reaction, reducing light absorption to half the solar spectrum in water splitting. Plasmonics transforms metal nanoparticles into antennas with resonances tuneable across the solar spectrum. If energy can be transferred from the plasmon to the semiconductor, light absorption in the semiconductor can be increased in thin films and occur at energies smaller than the band gap. This thesis investigates why, despite this potential, plasmonic solar energy harvesting techniques rarely appear in top performing solar architectures. To accomplish this goal, the possible plasmonic enhancement mechanisms for solar energy conversion were identified, isolated, and optimized by combining systematic sample design with transient absorption spectroscopy, photoelectrochemical and photocatalytic testing, and theoretical development. Specifically, metal semiconductor nanostructures were designed to modulate the plasmon's scattering, hot carrier, and near field interactions as well as remove heating and self-catalysis effects. Transient absorption spectroscopy then revealed how the structure design affected energy and charge carrier transfer between metal and semiconductor. Correlating this data with wavelength-dependent photoconversion efficiencies and theoretical developments regarding metal-semiconductor interactions identified the origin of the plasmonic enhancement. Using this methodology, it has first been proven that three plasmonic enhancement routes are

  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. A nonlinear piezoelectric energy harvester for various mechanical motions

    Science.gov (United States)

    Fan, Kangqi; Chang, Jianwei; Pedrycz, Witold; Liu, Zhaohui; Zhu, Yingmin

    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.

  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. 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

  7. 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.

  8. A new piezoelectric energy harvesting design concept: multimodal energy harvesting skin.

    Science.gov (United States)

    Lee, Soobum; Youn, Byeng D

    2011-03-01

    This paper presents an advanced design concept for a piezoelectric energy harvesting (EH), referred to as multimodal EH skin. This EH design facilitates the use of multimodal vibration and enhances power harvesting efficiency. The multimodal EH skin is an extension of our previous work, EH skin, which was an innovative design paradigm for a piezoelectric energy harvester: a vibrating skin structure and an additional thin piezoelectric layer in one device. A computational (finite element) model of the multilayered assembly - the vibrating skin structure and piezoelectric layer - is constructed and the optimal topology and/or shape of the piezoelectric layer is found for maximum power generation from multiple vibration modes. A design rationale for the multimodal EH skin was proposed: designing a piezoelectric material distribution and external resistors. In the material design step, the piezoelectric material is segmented by inflection lines from multiple vibration modes of interests to minimize voltage cancellation. The inflection lines are detected using the voltage phase. In the external resistor design step, the resistor values are found for each segment to maximize power output. The presented design concept, which can be applied to any engineering system with multimodal harmonic-vibrating skins, was applied to two case studies: an aircraft skin and a power transformer panel. The excellent performance of multimodal EH skin was demonstrated, showing larger power generation than EH skin without segmentation or unimodal EH skin. PMID:21429855

  9. Biochemical, histologic, and biomechanical characterization of native and decellularized flexor tendon specimens harvested from the pelvic limbs of orthopedically normal dogs.

    Science.gov (United States)

    Balogh, Daniel G; Biskup, Jeffery J; O'Sullivan, M Gerard; Scott, Ruth M; Groschen, Donna; Evans, Richard B; Conzemius, Michael G

    2016-04-01

    OBJECTIVE To evaluate the biochemical and biomechanical properties of native and decellularized superficial digital flexor tendons (SDFTs) and deep digital flexor tendons (DDFTs) harvested from the pelvic limbs of orthopedically normal dogs. SAMPLE 22 commercially supplied tendon specimens (10 SDFT and 12 DDFT) harvested from the pelvic limbs of 13 canine cadavers. PROCEDURES DNA, glycosaminoglycan, collagen, and protein content were measured to biochemically compare native and decellularized SDFT and DDFT specimens. Mechanical testing was performed on 4 groups consisting of native tendons (5 SDFTs and 6 DDFTs) and decellularized tendons (5 SDFTs and 6 DDFTs). All tendons were preconditioned, and tension was applied to failure at 0.5 mm/s. Failure mode was video recorded for each tendon. Load-deformation and stress-strain curves were generated; calculations were performed to determine the Young modulus and stiffness. Biochemical and biomechanical data were statistically compared by use of the Wilcoxon rank sum test. RESULTS Decellularized SDFT and DDFT specimens had significantly less DNA content than did native tendons. No significant differences were identified between native and decellularized specimens with respect to glycosaminoglycan, collagen, or protein content. Biomechanical comparison yielded no significant intra- or intergroup differences. All DDFT constructs failed at the tendon-clamp interface, whereas nearly half (4/10) of the SDFT constructs failed at midsubstance. CONCLUSIONS AND CLINICAL RELEVANCE Decellularized commercial canine SDFT and DDFT specimens had similar biomechanical properties, compared with each other and with native tendons. The decellularization process significantly decreased DNA content while minimizing loss of extracellular matrix components. Decellularized canine flexor tendons may provide suitable, biocompatible graft scaffolds for bioengineering applications such as tendon or ligament repair. PMID:27027838

  10. Hybrid energy harvesting/transmission system for embedded devices

    Science.gov (United States)

    Hehr, Adam; Park, Gyuhae; Farinholt, Kevin

    2012-04-01

    In most energy harvesting applications the need for a reliable long-term energy supply is essential in powering embedded sensing and control electronics. The goal of many harvesters is to extract energy from the ambient environment to power hardware; however in some applications there may be conditions in which the harvester's performance cannot meet all of the demands of the embedded electronics. One method for addressing this shortfall is to supplement harvested power through the transmission of wireless energy, a concept that has successfully been demonstrated by the authors in previous studies. In this paper we present our findings on the use of a single electromagnetic coil to harvest kinetic energy in a solenoid configuration, as well as background and directed wireless energy in the 2.4 GHz radio frequency (RF) bands commonly used in WiFi and cellular phone applications. The motivation for this study is to develop a compact energy harvester / receiver that conserves physical volume, while providing multi-modal energy harvesting capabilities. As with most hybrid systems there are performance trade-offs that must be considered when capturing energy from different physical sources. As part of this paper, many of the issues related to power transmission, physical design, and potential applications are addressed for this device.

  11. Note: Vibration energy harvesting based on a round acoustic fence.

    Science.gov (United States)

    Cui, Xiao-bin; Huang, Cheng-ping; Hu, Jun-hui

    2015-07-01

    An energy harvester based on a round acoustic fence (RAF) has been proposed and studied. The RAF is composed of cylindrical stubs stuck in a circular array on a thin metal plate, which can confine the acoustic energy efficiently. By removing one stub and thus opening a small gap in the RAF, acoustic leakage with larger intensity can be produced at the gap opening. With the vibration source surrounded by the RAF, the energy harvesting at the gap opening has a wide bandwidth and is insensitive to the position of the vibration source. The results may have potential applications in harvesting the energy of various vibration sources in solid structure. PMID:26233415

  12. 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 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......, harvesting energy from the radio frequency (RF) waves gives the lowest system design. Previous research on RF energy harvesting is based on the model that the radio energy is omnidirectional in the air. In this paper, a directional transmission/receiving model is proposed which can further overcome the path...

  13. Nonlinear Modeling and Analysis of a Vertical Springless Energy Harvester

    Directory of Open Access Journals (Sweden)

    Abdel-Rahman Eihab

    2012-07-01

    Full Text Available Harvesting energy from ambient sources has attracted the attention of researchers and scientists over the last few decades. While solar, thermal and wind energies have been exploited over the years, a new type of energy that has emerged in recent years, and is the subject of many research projects, is vibration energy harvesting. In this paper we will describe and analyze a recently proposed vibration energy harvester, namely the “Springless” vibration energy harvester. In this study, we will model and analyze the “Springless” vibration energy harvester in the vertical configuration. The vertically-aligned configuration is used when vibrations are predominantly in the vertical direction. Test results of a prototype model as well as results form a mathematical model describing the behavior of the harvester are presented. Test results show that the “Springless” energy vibration harvester behaves as a softening nonlinear oscillator for excitations above 0:2g with its center frequency shifting to the right. Similar results were obtained using a mathematical model of the underlying impact oscillator.

  14. Acoustic energy harvesting based on a planar acoustic metamaterial

    Science.gov (United States)

    Qi, Shuibao; Oudich, Mourad; Li, Yong; Assouar, Badreddine

    2016-06-01

    We theoretically report on an innovative and practical acoustic energy harvester based on a defected acoustic metamaterial (AMM) with piezoelectric material. The idea is to create suitable resonant defects in an AMM to confine the strain energy originating from an acoustic incidence. This scavenged energy is converted into electrical energy by attaching a structured piezoelectric material into the defect area of the AMM. We show an acoustic energy harvester based on a meta-structure capable of producing electrical power from an acoustic pressure. Numerical simulations are provided to analyze and elucidate the principles and the performances of the proposed system. A maximum output voltage of 1.3 V and a power density of 0.54 μW/cm3 are obtained at a frequency of 2257.5 Hz. The proposed concept should have broad applications on energy harvesting as well as on low-frequency sound isolation, since this system acts as both acoustic insulator and energy harvester.

  15. 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 ...

  16. 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.

  17. A vibration energy harvester using magnet/piezoelectric composite transducer

    Science.gov (United States)

    Qiu, Jing; Chen, Hengjia; Wen, Yumei; Li, Ping; Yang, Jin; Li, Wenli

    2014-05-01

    In this research, a vibration energy harvester employing the magnet/piezoelectric composite transducer to convert mechanical vibration energy into electrical energy is presented. The electric output performance of a vibration energy harvester has been investigated. Compared to traditional magnetoelectric transducer, the proposed vibration energy harvester has some remarkable characteristic which do not need binder. The experimental results show that the presented vibration energy harvester can obtain an average power of 0.39 mW for an acceleration of 0.6g at frequency of 38 Hz. Remarkably, this power is a very encouraging power figure that gives the prospect of being able to power a widely range of wireless sensors in wireless sensor network.

  18. Piezoelectric and electromagnetic respiratory effort energy harvesters.

    Science.gov (United States)

    Shahhaidar, Ehsaneh; Padasdao, Bryson; Romine, R; Stickley, C; Boric-Lubecke, Olga

    2013-01-01

    The movements of the torso due to normal breathing could be harvested as an alternative, and renewable power source for an ultra-low power electronic device. The same output signal could also be recorded as a physiological signal containing information about breathing, thus enabling self-powered wearable biosensors/harvesters. In this paper, the selection criteria for such a biosensor, optimization procedure, trade-offs, and challenges as a sensor and harvester are presented. The empirical data obtained from testing different modules on a mechanical torso and a human subject demonstrated that an electromagnetic generator could be used as an unobtrusive self-powered medical sensor by harvesting more power, offering reasonable amount of output voltage for rectification purposes, and detecting respiratory effort. PMID:24110468

  19. A MEMS vibration energy harvester for automotive applications

    Science.gov (United States)

    van Schaijk, R.; Elfrink, R.; Oudenhoven, J.; Pop, V.; Wang, Z.; Renaud, M.

    2013-05-01

    The objective of this work is to develop MEMS vibration energy harvesters for tire pressure monitoring systems (TPMS), they can be located on the rim or on the inner-liner of the car tire. Nowadays TPMS modules are powered by batteries with a limited lifetime. A large effort is ongoing to replace batteries with small and long lasting power sources like energy harvesters [1]. The operation principle of vibration harvesters is mechanical resonance of a seismic mass, where mechanical energy is converted into electrical energy. In general, vibration energy harvesters are of specific interest for machine environments where random noise or repetitive shock vibrations are present. In this work we present the results for MEMS based vibration energy harvesting for applying on the rim or inner-liner. The vibrations on the rim correspond to random noise. A vibration energy harvester can be described as an under damped mass-spring system acting like a mechanical band-pass filter, and will resonate at its natural frequency [2]. At 0.01 g2/Hz noise amplitude the average power can reach the level that is required to power a simple wireless sensor node, approximately 10 μW [3]. The dominant vibrations on the inner-liner consist mainly of repetitive high amplitude shocks. With a shock, the seismic mass is displaced, after which the mass will "ring-down" at its natural resonance frequency. During the ring-down period, part of the mechanical energy is harvested. On the inner-liner of the tire repetitive (one per rotation) high amplitude (few hundred g) shocks occur. The harvester enables an average power of a few tens of μW [4], sufficient to power a more sophisticated wireless sensor node that can measure additional tire-parameters besides pressure. In this work we characterized MEMS vibration energy harvesters for noise and shock excitation. We validated their potential for TPMS modules by measurements and simulation.

  20. Autonomous energy harvesting embedded sensors for border security applications

    Science.gov (United States)

    Hande, Abhiman; Shah, Pradeep; Falasco, James N.; Weiner, Doug

    2010-04-01

    Wireless networks of seismic sensors have proven to be a valuable tool for providing security forces with intrusion alerts even in densely forested areas. The cost of replenishing the power source is one of the primary obstacles preventing the widespread use of wireless sensors for passive barrier protection. This paper focuses on making use of energy from multiple sources to power these sensors. A system comprising of Texas Micropower's (TMP's) energy harvesting device and Crane Wireless Monitoring Solutions' sensor nodes is described. The energy harvesters are suitable for integration and for low cost, high volume production. The harvesters are used for powering sensors in Crane's wireless hub and spoke type sensor network. TMP's energy harvesting methodology is based on adaptive power management circuits that allow harvesting from multiple sources making them suitable for underground sensing/monitoring applications. The combined self-powered energy harvesting solutions are expected to be suitable for broad range of defense and industry applications. Preliminary results have indicated good feasibility to use a single power management solution that allows multi-source energy harvesting making such systems practical in remote sensing applications.

  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. Sustained operation of sensor nodes with energy harvesters and supercapacitors

    Energy Technology Data Exchange (ETDEWEB)

    Renner, Bernd-Christian

    2013-06-01

    Sensor nodes powered by energy harvesters and supercapacitors open the door to unlimited and uninterrupted operation. This dissertation closes the persistent gap of system integration w.r.t. holistic online energy assessment, develops a new concept for harvest forecasting while assessing the behavior and quality of known approaches, and proposes a novel load adaptation scheme to achieve sustained and uniform sensor node operation with low complexity and computational overhead. For this purpose, a prototype of an energy harvester with a supercapacitor for off-the-shelf sensor nodes is developed and used for practical evaluation.

  3. Piezo-magnetic energy harvesting from movement of the head

    Science.gov (United States)

    Delnavaz, Aidin; Voix, Jérémie

    2015-12-01

    This paper reports the design, modeling, optimization and testing of the piezomagnetic energy harvester that is capable of converting non-harmonic movement of the human head into electricity. The rolling magnet and doubly-clamped piezoelectric configuration of the device makes the energy harvesting from small-amplitude and low-frequency movements of the human head efficient. In addition, the device can inconspicuously be integrated with the glasses. the experimental results show that the energy harvester device could deliver the maximum instantaneous power of 0.5 μW to the impedance matched resistive load.

  4. Characterization of Direct Piezoelectric Properties for Vibration Energy Harvesting

    Energy Technology Data Exchange (ETDEWEB)

    Yoshimura, Takeshi; Miyabuchi, Hiroki; Ashida, Atsushi; Fujimura, Norifumi [Osaka Prefecture University, 1-1 Gakuen-cho, Naka-ku, Sakai, Osaka, 599-8531 (Japan); Murakami, Syuichi, E-mail: tyoshi@pe.osakafu-u.ac.jp [Technology Research Institute of Osaka Prefecture, 2-7-1 Ayumino, Izumi, Osaka, 594-1157 (Japan)

    2011-10-29

    Direct piezoelectric effect of Pb(Zr,Ti)O{sub 3} (PZT) thin films was investigated to discuss the application of ferroelectric films to vibration energy harvesting. From the model of the piezoelectric vibration energy harvester, it was found that the figure of merit (FOM) is proportional of the square of the effective transverse piezoelectric coefficient e{sub 31,f}. The e{sub 31,f} coefficient of PZT films were measured by substrate bending method. Furthermore, it was found that the e{sub 31,f} coefficient increases with increasing strain, which is favourable for the vibration energy harvesting.

  5. Modelling piezoelectric energy harvesting potential in an educational building

    International Nuclear Information System (INIS)

    Highlights: • Energy harvesting potential of commercialized piezoelectric tiles is analyzed. • The parameters which will affect the energy harvesting efficiency are determined. • The potential could cover 0.5% of the total energy usage of the library building. • A simplified evaluation indicator is proposed to test the considered paving area. - Abstract: In this paper, potential application of a commercial piezoelectric energy harvester in a central hub building at Macquarie University in Sydney, Australia is examined and discussed. Optimization of the piezoelectric tile deployment is presented according to the frequency of pedestrian mobility and a model is developed where 3.1% of the total floor area with the highest pedestrian mobility is paved with piezoelectric tiles. The modelling results indicate that the total annual energy harvesting potential for the proposed optimized tile pavement model is estimated at 1.1 MW h/year. This potential energy generation may be further increased to 9.9 MW h/year with a possible improvement in piezoelectric energy conversion efficiency integrated into the system. This energy harvesting potential would be sufficient to meet close to 0.5% of the annual energy needs of the building. The study confirms that locating high traffic areas is critical for optimization of the energy harvesting efficiency, as well as the orientation of the tile pavement significantly affects the total amount of the harvested energy. A Density Flow evaluation is recommended in this study to qualitatively evaluate the piezoelectric power harvesting potential of the considered area based on the number of pedestrian crossings per unit time

  6. 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...

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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...

  12. 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.

  13. Microbial fuel cell energy harvesting using synchronous flyback converter

    Science.gov (United States)

    Alaraj, Muhannad; Ren, Zhiyong Jason; Park, Jae-Do

    2014-02-01

    Microbial Fuel Cells (MFCs) use biodegradable substrates, such as wastewater and marine sediments to generate electrical energy. To harvest more energy from an MFC, power electronic converters have recently been used to replace resistors or charge pumps, because they have superior controllability on MFC's operating point and higher efficiency in energy storage for different applications. Conventional diode-based energy harvesters suffer from low efficiency because of the energy losses through the diode. Replacing the diode with a MOSFET can reduce the conduction loss, but it requires an isolated gate signal to control the floating secondary MOSFET, which makes the control circuitry complex. This study presents a new MFC energy harvesting regime using a synchronous flyback converter, which implements a transformer-based harvester with much simpler configuration and improves harvesting efficiency by 37.6% compared to a diode based boost converter, from 33.5% to 46.1%. The proposed harvester was able to store 2.27 J in the output capacitor out of 4.91 J generated energy from the MFC, while the boost converter can capture 1.67 J from 4.95 J.

  14. Energy harvesting from low frequency applications using piezoelectric materials

    International Nuclear Information System (INIS)

    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

  15. 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.

  16. 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....

  17. 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.

  18. Simultaneous Energy Harvesting and Vibration Control via Piezoelectric Materials

    OpenAIRE

    Wang, Ya

    2012-01-01

    This work examines a novel concept and design of simultaneous energy harvesting and vibration control on the same host structure. The motivating application is a multifunctional composite sandwich wing spar for a small Unmanned Aerial Vehicle (UAV) with the goal of providing self-contained gust alleviation. The basic idea is that the wing itself is able to harvest energy from the ambient vibrations along with available sunlight during normal flight. If the wing experiences any strong wind gus...

  19. Effects of springs on a pendulum electromechanical energy harvester

    Directory of Open Access Journals (Sweden)

    Arnaud Notué Kadjie

    2014-01-01

    Full Text Available This paper studies a model of energy harvester that consists of an electromechanical pendulum system subjected to nonlinear springs. The output power is analyzed in terms of the intrinsic parameters of the device leading to optimal parameters for energy harvesting. It is found that in an appropriate range of the springs constant, the power attains higher values as compared to the case without springs. The dynamical behavior of the device shows transition to chaos.

  20. Energy harvesting aware hybrid MAC protocol for WBANs

    OpenAIRE

    Ibarra, Ernesto; Antonopoulos, Angelos; KARTSAKLI, Elli; Verikoukis, Christos

    2013-01-01

    In this paper, we propose a hybrid polling Medium Access Control (MAC) protocol with Human Energy Harvesting capabilities, called HEH-BMAC, designed for Wireless Body Area Networks (WBANs). The proposed protocol uses a dynamic schedule algorithm to combine User Identification polling (ID) and Probabilistic Contention (PC) random access, adapting the network operation to the random, time-varying nature of the human energy harvesting sources. HEH-BMAC offers different levels of node priorities ...

  1. 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.

  2. Multislot Simultaneous Spectrum Sensing and Energy Harvesting in Cognitive Radio

    Directory of Open Access Journals (Sweden)

    Xin Liu

    2016-07-01

    Full Text Available In cognitive radio (CR, the spectrum sensing of the primary user (PU may consume some electrical power from the battery capacity of the secondary user (SU, resulting in a decrease in the transmission power of the SU. In this paper, a multislot simultaneous spectrum sensing and energy harvesting model is proposed, which uses the harvested radio frequency (RF energy of the PU signal to supply the spectrum sensing. In the proposed model, the sensing duration is divided into multiple sensing slots consisting of one local-sensing subslot and one energy-harvesting subslot. If the PU is detected to be present in the local-sensing subslot, the SU will harvest RF energy of the PU signal in the energy-harvesting slot, otherwise, the SU will continue spectrum sensing. The global decision on the presence of the PU is obtained through combining local sensing results from all the sensing slots by adopting “Or-logic Rule”. A joint optimization problem of sensing time and time splitter factor is proposed to maximize the throughput of the SU under the constraints of probabilities of false alarm and detection and energy harvesting. The simulation results have shown that the proposed model can clearly improve the maximal throughput of the SU compared to the traditional sensing-throughput tradeoff model.

  3. 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.

  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. Modeling of a honeycomb-shaped pyroelectric energy harvester for human body heat harvesting

    Science.gov (United States)

    Kim, Myoung-Soo; Jo, Sung-Eun; Ahn, Hye-Rin; Kim, Yong-Jun

    2015-06-01

    Pyroelectric conversion can be used for thermal energy harvesting in lieu of thermoelectric conversion. In the case of human body energy harvesting, the general pyroelectric energy harvester (PEH) cannot be applied because the weak body heat can hardly penetrate the protecting layer to reach the pyroelectric material. This paper presents the realization of a honeycomb-shaped PEH (H-PEH) and a modeling method of the electrode and hole areas. The fabricated H-PEH successfully generated electrical energy using human body heat. The H-PEH with a 1:1.5 electrode-and-hole area ratio showed the best performance. To verify the human energy harvesting, we evaluated the characteristics of conventional PEH and H-PEH when body heat was used as a heat source. The maximum power of the H-PEH was 0.06 and 0.16 μW at wind velocities of 2 and 4 m s-1, respectively. These output power values of the H-PEH were 200 and 224% larger than those of the PEH, respectively, according to the wind velocity.

  6. A hybrid electromagnetic energy harvesting device for low frequency vibration

    Science.gov (United States)

    Jung, Hyung-Jo; Kim, In-Ho; Min, Dong Yi; Sim, Sung-Han; Koo, Jeong-Hoi

    2013-04-01

    An electromagnetic energy harvesting device, which converts a translational base motion into a rotational motion by using a rigid bar having a moving mass pivoted on a hinged point with a power spring, has been recently developed for use of civil engineering structures having low natural frequencies. The device utilizes the relative motion between moving permanent magnets and a fixed solenoid coil in order to harvest electrical power. In this study, the performance of the device is enhanced by introducing a rotational-type generator at a hinged point. In addition, a mechanical stopper, which makes use of an auxiliary energy harvesting part to further improve the efficiency, is incorporated into the device. The effectiveness of the proposed hybrid energy harvesting device based on electromagnetic mechanism is verified through a series of laboratory tests.

  7. Optimal Design of RF Energy Harvesting Device Using Genetic Algorithm

    Science.gov (United States)

    Mori, T.; Sato, Y.; Adriano, R.; Igarashi, H.

    2015-11-01

    This paper presents optimal design of an RF energy harvesting device using genetic algorithm (GA). In the present RF harvester, a planar spiral antenna (PSA) is loaded with matching and rectifying circuits. On the first stage of the optimal design, the shape parameters of PSA are optimized using . Then, the equivalent circuit of the optimized PSA is derived for optimization of the circuits. Finally, the parameters of RF energy harvesting circuit are optimized to maximize the output power using GA. It is shown that the present optimization increases the output power by a factor of five. The manufactured energy harvester starts working when the input electric field is greater than 0.5 V/m.

  8. 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.

  9. 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. PMID:23366218

  10. Wideband energy harvesting using a combination of an optimized synchronous electric charge extraction circuit and a bistable harvester

    International Nuclear Information System (INIS)

    The challenge of variable vibration frequencies for energy harvesting calls for the development of wideband energy harvesters. Bistability has been proven to be a potential solution. Optimization of the energy extraction is another important objective for energy harvesting. Nonlinear synchronized switching techniques have demonstrated some of the best performances. This paper presents a novel energy harvesting solution which combines these two techniques: the OSECE (optimized synchronous electric charge extraction) technique is used along with a BSM (buckled-spring–mass) bistable generator to achieve wideband energy harvesting. The effect of the electromechanical coupling coefficient on the harvested power for the bistable harvester with the nonlinear energy extraction technique is discussed for the first time. The performances of the proposed solution for different levels of electromechanical coupling coefficients in the cases of chirp and noise excitations are compared against the performances of the bistable harvester with the standard technique. It is shown that the OSECE technique is a much better option for wideband energy harvesting than the standard circuit. Moreover, the harvested energy is drastically increased for all excitations in the case of low electromechanical coupling coefficients. When the electromechanical coupling coefficient is high, the performance of the OSECE technique is not as good as the standard circuit for forward sweeps, but superior for the reverse sweep and band-limited noise cases. However, considering that real excitation signals are more similar to noise signals, the OSECE technique enhances the performance. (paper)

  11. 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.

  12. 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.

  13. 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.

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

    Science.gov (United States)

    Zhao, Jingjing; You, Zheng

    2014-01-01

    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. PMID:25019634

  15. 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. PMID:22622969

  16. 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.

  17. 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. PMID:27490707

  18. 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.

  19. Modeling and analysis of a horizontally-aligned energy harvester

    Directory of Open Access Journals (Sweden)

    Bendame M.

    2014-01-01

    Full Text Available In this paper we analyse an impact-type vibration energy harvester. In this study, the harvester is positioned so that the electromagnetic transducer moves along a horizontal linear guide when subjected to base excitations. The governing equation is a nonsmooth second order differential equation which cannot be solved analytically. Therefore, the averaging method is used to investigate its response. Experimental results are compared with the analytical solution to validate it. The results show that the existence of the nonlinearity in the system enables harvesting at low frequencies, increase the bandwidth, and enhances the output power significantly.

  20. Compact electret energy harvester with high power output

    Science.gov (United States)

    Pondrom, P.; Sessler, G. M.; Bös, J.; Melz, T.

    2016-08-01

    Compact electret energy harvesters, based on a design recently introduced, are presented. Using electret surface potentials in the 400 V regime and a seismic mass of 10 g, it was possible to generate output power up to 0.6 mW at 36 Hz for an input acceleration of 1 g. Following the presentation of an analytical model allowing for the calculation of the power generated in a load resistance at the resonance frequency of the harvesters, experimental results are shown and compared to theoretical predictions. Finally, the performance of the electret harvesters is assessed using a figure of merit.

  1. Design optimization of piezoelectric energy harvester subject to tip excitation

    Energy Technology Data Exchange (ETDEWEB)

    Park, Ju Il; Kwak, Byung Man [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of); Lee, Soo Bum [University of Notre Dame, Notre Dame (United States)

    2012-01-15

    This research proposes a new design for a cantilever-type piezoelectric energy harvester in which a free tip is excited by any rotary motion of mechanical devices. A coupled field finite element model for the harvester is constructed using ANSYS and verification study is performed. Design optimization on the shape of the harvester is done to maximize output power. The design optimization result shows excellent performance when compared to a simple rectangular cantilever or the well-known tapered cantilever. The design results are prototyped and their improved performances are experimentally attested.

  2. 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. PMID:23112598

  3. Design of a bimorph piezoelectric energy harvester for railway monitoring

    International Nuclear Information System (INIS)

    Wireless sensor network is one of prospective methods for railway monitoring due to the long term operation and low maintenance performances. How to supply power to the wireless sensor nodes has drawn much attention recently. In railway monitoring, the idea of converting ambient vibration energy from vibration of railway track induced by passing trains to electric energy has made it a potential way for powering the wireless sensor nodes. In this paper, a bimorph cantilever piezoelectric energy harvester was designed based on a single degree of freedom model. Experimental test was also performed to validate the design. The first natural frequency of the bimorph piezoelectric energy harvester was decreased from 117.1 Hz to 65.2 Hz by adding 4 gram tip mass to the free end of the 8.6 gram energy harvester. In addition, the power generation of the piezoelectric energy harvester with 4 gram tip mass at resonant frequency was increased from 0.14 mW to 0.74 mW from 2.06 m/s2 base excitation compared to stand alone piezoelectric energy harvester without tip mass

  4. 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.

  5. 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.

  6. Design of a bimorph piezoelectric energy harvester for railway monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Li, Jingcheng; Jang, Shinae; Tang, Jiong [Univ. of Connecticut, Connecticut (United States)

    2012-12-15

    Wireless sensor network is one of prospective methods for railway monitoring due to the long term operation and low maintenance performances. How to supply power to the wireless sensor nodes has drawn much attention recently. In railway monitoring, the idea of converting ambient vibration energy from vibration of railway track induced by passing trains to electric energy has made it a potential way for powering the wireless sensor nodes. In this paper, a bimorph cantilever piezoelectric energy harvester was designed based on a single degree of freedom model. Experimental test was also performed to validate the design. The first natural frequency of the bimorph piezoelectric energy harvester was decreased from 117.1 Hz to 65.2 Hz by adding 4 gram tip mass to the free end of the 8.6 gram energy harvester. In addition, the power generation of the piezoelectric energy harvester with 4 gram tip mass at resonant frequency was increased from 0.14 mW to 0.74 mW from 2.06 m/s{sup 2} base excitation compared to stand alone piezoelectric energy harvester without tip mass.

  7. 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.

  8. 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.

  9. Energy Harvesting Using an Analog Circuit under Multimodal Vibration

    OpenAIRE

    Shigeru Shimose; Kanjuro Makihara; Junjiro Onoda

    2013-01-01

    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 sin...

  10. 3D, wideband vibro-impacting-based piezoelectric energy harvester

    OpenAIRE

    Qiangmo Yu; Jin Yang; Xihai Yue; Aichao Yang; Jiangxin Zhao; Nian Zhao; Yumei Wen; Ping Li

    2015-01-01

    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...

  11. 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

  12. 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.

  13. 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.

  14. 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-...

  15. 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.

  16. 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.

  17. A Skin-attachable Flexible Piezoelectric Pulse Wave Energy Harvester

    International Nuclear Information System (INIS)

    We present a flexible piezoelectric generator, capable to harvest energy from human arterial pulse wave on the human wrist. Special features and advantages of the flexible piezoelectric generator include the multi-layer device design with contact windows and the simple fabrication process for the higher flexibility with the better energy harvesting efficiency. We have demonstrated the design effectiveness and the process simplicity of our skin- attachable flexible piezoelectric pulse wave energy harvester, composed of the sensitive P(VDF-TrFE) piezoelectric layer on the flexible polyimide support layer with windows. We experimentally characterize and demonstrate the energy harvesting capability of 0.2∼1.0μW in the Human heart rate range on the skin contact area of 3.71cm2. Additional physiological and/or vital signal monitoring devices can be fabricated and integrated on the skin attachable flexible generator, covered by an insulation layer; thus demonstrating the potentials and advantages of the present device for such applications to the flexible multi-functional selfpowered artificial skins, capable to detect physiological and/or vital signals on Human skin using the energy harvested from arterial pulse waves

  18. 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.

  19. Energy-harvesting shock absorber with a mechanical motion rectifier

    Science.gov (United States)

    Li, Zhongjie; Zuo, Lei; Kuang, Jian; Luhrs, George

    2013-02-01

    Energy-harvesting shock absorbers are able to recover the energy otherwise dissipated in the suspension vibration while simultaneously suppressing the vibration induced by road roughness. They can work as a controllable damper as well as an energy generator. An innovative design of regenerative shock absorbers is proposed in this paper, with the advantage of significantly improving the energy harvesting efficiency and reducing the impact forces caused by oscillation. The key component is a unique motion mechanism, which we called ‘mechanical motion rectifier (MMR)’, to convert the oscillatory vibration into unidirectional rotation of the generator. An implementation of a MMR-based harvester with high compactness is introduced and prototyped. A dynamic model is created to analyze the general properties of the motion rectifier by making an analogy between mechanical systems and electrical circuits. The model is capable of analyzing electrical and mechanical components at the same time. Both simulation and experiments are carried out to verify the modeling and the advantages. The prototype achieved over 60% efficiency at high frequency, much better than conventional regenerative shock absorbers in oscillatory motion. Furthermore, road tests are done to demonstrate the feasibility of the MMR shock absorber, in which more than 15 Watts of electricity is harvested while driving at 15 mph on a smooth paved road. The MMR-based design can also be used for other applications of vibration energy harvesting, such as from tall buildings or long bridges.

  20. Cooperative Energy Harvesting-Adaptive MAC Protocol for WBANs

    Directory of Open Access Journals (Sweden)

    Volker Esteves

    2015-05-01

    Full Text Available 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.

  1. 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.

  2. 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.

  3. 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. PMID:27410898

  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. Vibration energy harvesting with aluminum nitride-based piezoelectric devices

    International Nuclear Information System (INIS)

    This paper describes the measurement results of piezoelectric energy harvesters with aluminum nitride (AlN) as a piezoelectric material. AlN was chosen for its material properties and for its well-known sputter deposition process. For AlN devices a high optimum load resistance is required, which is favorable due to the high resulting voltage level. The output power harvested from mechanical vibrations has been measured on micromachined harvesters with different geometries. The resonance frequencies ranged from 200 up to 1200 Hz. The packaged devices had limited output powers and quality factors due to air damping caused by the package. A maximum output power of 60 µW has been measured on an unpackaged device at an acceleration of 2.0 g and at a resonance frequency of 572 Hz. The package of the harvester requires special attention, since air damping can significantly decrease the maximum power output

  6. Energy harvesting from human motion: exploiting swing and shock excitations

    International Nuclear Information System (INIS)

    Modern compact and low power sensors and systems are leading towards increasingly integrated wearable systems. One key bottleneck of this technology is the power supply. The use of energy harvesting techniques offers a way of supplying sensor systems without the need for batteries and maintenance. In this work we present the development and characterization of two inductive energy harvesters which exploit different characteristics of the human gait. A multi-coil topology harvester is presented which uses the swing motion of the foot. The second device is a shock-type harvester which is excited into resonance upon heel strike. Both devices were modeled and designed with the key constraint of device height in mind, in order to facilitate the integration into the shoe sole. The devices were characterized under different motion speeds and with two test subjects on a treadmill. An average power output of up to 0.84 mW is achieved with the swing harvester. With a total device volume including the housing of 21 cm3 a power density of 40 μW cm−3 results. The shock harvester generates an average power output of up to 4.13 mW. The power density amounts to 86 μW cm−3 for the total device volume of 48 cm3. Difficulties and potential improvements are discussed briefly. (paper)

  7. Hybrid acoustic energy harvesting using combined electromagnetic and piezoelectric conversion.

    Science.gov (United States)

    Khan, Farid Ullah; Izhar

    2016-02-01

    This paper reports a novel hybrid acoustic energy harvester. The harvester utilizes both the electromagnetic and piezoelectric conversion mechanisms simultaneously to convert the ambient acoustical noise into electrical power for self-powered wireless sensor nodes. The proposed harvester is comprised of a Helmholtz resonator, two magnets mounted on a piezoelectric plate, and a wound coil located under the magnets. The harvester is characterized both under harmonic and real random acoustical excitations. In-lab, under harmonic acoustical excitation at a sound pressure level of 130 dB and frequency of 2.1 kHz, an optimum power of 2.86 μW (at 114 Ω optimum load) is obtained from electromagnetic conversion and 50 μW (at 1000 Ω optimum load) is generated by the piezoelectric harvester's part. Moreover, in real acoustical environment of a domestic electric generator the peak voltages of 40 and 123 mV are produced by the electromagnetic and piezoelectric portions of the acoustic energy harvester. PMID:26931884

  8. 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.

  9. 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...

  10. Active and reactive power in stochastic resonance for energy harvesting

    OpenAIRE

    Kubota, Madoka; Takahashi, Ryo(Graduate School of Science and Engineering, Shimane University, Matsue, 690-8504, Japan); Hikihara, Takashi

    2015-01-01

    A power allocation to active and reactive power in stochastic resonance is discussed for energy harvesting from mechanical noise. It is confirmed that active power can be increased at stochastic resonance, in the same way of the relationship between energy and phase at an appropriate setting in resonance.

  11. 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.

  12. 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.

  13. Issues in mathematical modeling of piezoelectric energy harvesters

    International Nuclear Information System (INIS)

    The idea of vibration-to-electric energy conversion for powering small electronic components by using the ambient vibration energy has been investigated by researchers from different disciplines in the last decade. Among the possible transduction mechanisms, piezoelectric transduction has received the most attention for converting ambient vibrations to useful electrical energy. In the last five years, there have been a considerable number of publications using various models for the electromechanical behavior of piezoelectric energy harvester beams. The models used in the literature range from elementary single-degree-of-freedom (SDOF) models to approximate distributed parameter models as well as analytical distributed parameter solution attempts. Because of the diverse nature of researchers working in energy harvesting (including electrical, mechanical and materials engineers), several oversimplified and incorrect physical assumptions have been propagated in the literature. Issues of the correct formulation for piezoelectric coupling, correct physical modeling, use of low fidelity models, incorrect base motion modeling, and the use of static expressions in a fundamentally dynamic problem are discussed and clarified here. These common indiscretions, which have been repeated in the existing piezoelectric energy harvesting literature, are addressed and clarified with improved models, and examples are provided. This paper aims to provide corrections and necessary clarifications for researchers from different engineering disciplines interested in electromechanical modeling of piezoelectric energy harvesters

  14. 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.

  15. 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. PMID:24591604

  16. 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.

  17. Low-Frequency Meandering Piezoelectric Vibration Energy Harvester

    OpenAIRE

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

    2012-01-01

    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 mu W and 5.02 mu W/mm(3)/g(2), respectively, when excited by an acceleration magnitude of 0.2 g at 49.7 Hz. Th...

  18. 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.

  19. 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-sided). An......-conditioning circuit is investigated for both continuous and burst power supply applications.......-sided). An analytical analysis is complemented by 2-D finite element method simulations, where the fringing field effect on a plane capacitor is studied and accounted for by an effective area that is well fitted by a sinusoidal function of the displacement of the proof mass. From analytical calculations, we prove...

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

    Science.gov (United States)

    Lu, Shaohua; Boussaid, Farid

    2015-01-01

    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. PMID:26610492

  1. 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.

  2. 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.

  3. Enhanced vibration based energy harvesting using embedded acoustic black holes

    Science.gov (United States)

    Zhao, L.; Semperlotti, F.; Conlon, S. C.

    2014-03-01

    In this paper, we investigate the use of dynamic structural tailoring via the concept of an Acoustic Black Hole (ABH) to enhance the performance of piezoelectric based energy harvesting from operational mechanical vibrations. The ABH is a variable thickness structural feature that can be embedded in the host structure allowing a smooth reduction of the phase velocity while minimizing the amplitude of reflected waves. The ABH thickness variation is typically designed according to power-law profiles. As a propagating wave enters the ABH, it is progressively slowed down while its wavelength is compressed. This effect results in structural areas with high energy density that can be exploited effectively for energy harvesting. The potential of ABH for energy harvesting is shown via a numerical study based on fully coupled finite element electromechanical models of an ABH tapered plate with surface mounted piezo-transducers. The performances of the novel design are evaluated by direct comparison with a non-tapered structure in terms of energy ratios and attenuation indices. Results show that the tailored structural design allows a drastic increase in the harvested energy both for steady state and transient excitation. Performance dependencies of key design parameters are also investigated.

  4. 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.

  5. 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.

  6. Piezoelectric energy harvesting for powering low power electronics

    Energy Technology Data Exchange (ETDEWEB)

    Leinonen, M.; Palosaari, J.; Hannu, J.; Juuti, J.; Jantunen, H. (Univ. of Oulu, Dept. of Electrical and Information Engineering (Finland)). email: jajuu@ee.oulu.fi

    2009-07-01

    Although wireless data transmission techniques are commonly used in electronic devices, they still suffer from wires for the power supply or from batteries which require charging, replacement and other maintenance. The vision for the portable electronics and industrial measurement systems of the future is that they are intelligent and independent on their energy supply. The major obstacle in this path is the energy source which enables all other functions and 'smartness' of the systems as the computing power is also restricted by the available energy. The development of long-life energy harvesters would reduce the need for batteries and wires thus enabling cost-effective and environment friendlier solutions for various applications such as autonomous wireless sensor networks, powering of portable electronics and other maintenance-free systems. One of the most promising techniques is mechanical energy harvesting e.g. by piezoelectric components where deformations produced by different means is directly converted to electrical charge via direct piezoelectric effect. Subsequently the electrical energy can be regulated or stored for further use. The total mechanical energy in vibration of machines can be very large and usually only a fraction of it can be transformed to electrical energy. Recently, piezoelectric vibration based energy harvesters have been developed widely for different energy consumption and application areas. As an example for low energy device an piezoelectric energy harvester based on impulse type excitations has been developed for active RFID identification. Moreover, piezoharvester with externally leveraged mechanism for force amplification was reported to be able to generate mean power of 0.4 mW from backpack movement. Significantly higher power levels are expected from larger scale testing in Israel, where piezoelectric material is embedded under active walking street, road, airport or railroad. The energy is harvested from human or

  7. 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

  8. A Method to Harvest Electrical Energy from Living Plants.

    Directory of Open Access Journals (Sweden)

    Ying Ying Choo

    2013-07-01

    Full Text Available In this paper, some fundamental investigations are established to demonstrate the potential of harvesting electrical energy from living plants. The energy is harvested by embedding electrodes into the plant to allow flow of ions and hence generate electricity. Multiple random tests have been conducted using different type of electrodes and plants as an attempt to determine the characteristics of the harvesting system. It is found that voltages are produced to greater or lesser extents by all tests where combination of copper-zinc and aloe vera produces the highest voltage. In addition, it is shown in this paper its ability to light up Light Emitting Diode (LED, digital clock and calculator which grants it a potential to be used for low power electrical consumption appliances in the future.

  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. 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.

  11. 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

  12. 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

  13. 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. PMID:26609400

  14. Innovative thermal energy harvesting for future autonomous applications

    International Nuclear Information System (INIS)

    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 and 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

  15. 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.

  16. Piezoelectric touch-sensitive flexible hybrid energy harvesting nanoarchitectures

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Dukhyun; Kim, Eok Su; Kim, Tae Sang; Lee, Sang Yoon; Choi, Jae-Young; Kim, Jong Min [Samsung Advanced Institute of Technology, Yongin 446-712 (Korea, Republic of); Lee, Keun Young; Lee, Kang Hyuck; Kim, Sang-Woo, E-mail: kimsw1@skku.edu, E-mail: jaeyoung88.choi@samsung.com [School of Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of)

    2010-10-08

    In this work, we report a flexible hybrid nanoarchitecture that can be utilized as both an energy harvester and a touch sensor on a single platform without any cross-talk problems. Based on the electron transport and piezoelectric properties of a zinc oxide (ZnO) nanostructured thin film, a hybrid cell was designed and the total thickness was below 500 nm on a plastic substrate. Piezoelectric touch signals were demonstrated under independent and simultaneous operations with respect to photo-induced charges. Different levels of piezoelectric output signals from different magnitudes of touching pressures suggest new user-interface functions from our hybrid cell. From a signal controller, the decoupled performance of a hybrid cell as an energy harvester and a touch sensor was confirmed. Our hybrid approach does not require additional assembly processes for such multiplex systems of an energy harvester and a touch sensor since we utilize the coupled material properties of ZnO and output signal processing. Furthermore, the hybrid cell can provide a multi-type energy harvester by both solar and mechanical touching energies.

  17. Piezoelectric touch-sensitive flexible hybrid energy harvesting nanoarchitectures.

    Science.gov (United States)

    Choi, Dukhyun; Lee, Keun Young; Lee, Kang Hyuck; Kim, Eok Su; Kim, Tae Sang; Lee, Sang Yoon; Kim, Sang-Woo; Choi, Jae-Young; Kim, Jong Min

    2010-10-01

    In this work, we report a flexible hybrid nanoarchitecture that can be utilized as both an energy harvester and a touch sensor on a single platform without any cross-talk problems. Based on the electron transport and piezoelectric properties of a zinc oxide (ZnO) nanostructured thin film, a hybrid cell was designed and the total thickness was below 500 nm on a plastic substrate. Piezoelectric touch signals were demonstrated under independent and simultaneous operations with respect to photo-induced charges. Different levels of piezoelectric output signals from different magnitudes of touching pressures suggest new user-interface functions from our hybrid cell. From a signal controller, the decoupled performance of a hybrid cell as an energy harvester and a touch sensor was confirmed. Our hybrid approach does not require additional assembly processes for such multiplex systems of an energy harvester and a touch sensor since we utilize the coupled material properties of ZnO and output signal processing. Furthermore, the hybrid cell can provide a multi-type energy harvester by both solar and mechanical touching energies. PMID:20829570

  18. Energy harvesting from electric power lines employing the Halbach arrays.

    Science.gov (United States)

    He, Wei; Li, Ping; Wen, Yumei; Zhang, Jitao; Lu, Caijiang; Yang, Aichao

    2013-10-01

    This paper proposes non-invasive energy harvesters to scavenge alternating magnetic field energy from electric power lines. The core body of a non-invasive energy harvester is a linear Halbach array, which is mounted on the free end of a piezoelectric cantilever beam. The Halbach array augments the magnetic flux density on the side of the array where the power line is placed and significantly lowers the magnetic field on the other side. Consequently, the magnetic coupling strength is enhanced and more alternating magnetic field energy from the current-carrying power line is converted into electrical energy. An analytical model is developed and the theoretical results verify the experimental results. A power of 566 μW across a 196 kΩ resistor is generated from a single wire, and a power of 897 μW across a 212 kΩ resistor is produced from a two-wire power cord carrying opposite currents at 10 A. The harvesters employing Halbach arrays for a single wire and a two-wire power cord, respectively, exhibit 3.9 and 3.2 times higher power densities than those of the harvesters employing conventional layouts of magnets. The proposed devices with strong response to the alternating currents are promising to be applied to electricity end-use environment in electric power systems. PMID:24182155

  19. Design and performance enhancement of hydraulic pressure energy harvesting systems

    Science.gov (United States)

    Skow, Ellen A.; Cunefare, Kenneth A.; Erturk, Alper

    2013-04-01

    Hydraulic pressure ripple energy harvesters generate low-power electricity from off-resonance dynamic pressure excitation of piezoelectric elements. Improvements were made to hydraulic pressure ripple energy harvester prototype performance. Hydraulic systems inherently have a high energy intensity associated with the mean pressure and flow. Accompanying the mean pressure is dynamic pressure ripple, which is caused by the action of pumps and actuators. Pressure ripple is generally a deterministic source with a periodic time-domain behavior conducive to energy harvesting. An energy harvester prototype was designed for generating low-power electricity from pressure ripples. These devices generate low-power electricity from off-resonance dynamic pressure excitation. The power produced per volume of device was increased through decreasing the device size and adding an inductor to the system circuit. The prototype device utilizes a piezoelectric stack with high overall capacitance allowing for inductance matching without using a switching circuit. Initial testing with addition of an inductor produced over 2.1 mW, an increase of 78% as compared to the device without the inductor. Two power output model simulations of a resistive-inductive circuit are analyzed: (1) ideal circuit case and (2) non-ideal circuit case with inductor internal resistance included.

  20. 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

  1. Nano-materials employment in energy harvesting and storage devices

    OpenAIRE

    Tamvakos, Dimitrios

    2015-01-01

    The present thesis focuses on the development of a new generation of miniature electronic devices by employing nano-scale materials. Specifically, ZnO nanowire arrays were investigated to increase the conversion efficiency of energy harvesting devices and graphene nano-platelets employed to enhance supercapacitors' energy storage capability. The results obtained in this work pave the way to the possibility of conceiving novel autonomous devices integrating both energy units. The present thesi...

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

    OpenAIRE

    Chris Knight; Scott McGarry

    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...

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

    OpenAIRE

    Shashank Priya; Jeongjin Yeo; Yoonseok Yang

    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 p...

  4. 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.

  5. Electromechanical decoupled model for cantilever-beam piezoelectric energy harvesters

    Science.gov (United States)

    Tan, T.; Yan, Z.; Hajj, M.

    2016-09-01

    Analysis of cantilever-based piezoelectric energy harvesting systems is usually performed using coupled equations that represent the mechanical displacement and the voltage output. These equations are then solved simultaneously. In contrast to this representation, we use analytical solutions of the governing equation to derive an algebraic equation of the power as a function of the beam displacement, electromechanical coefficients, and the load resistance. Such an equation can be more useful in the design of such harvesters. Particularly, the mechanical displacement is computed from a mechanical governing equation with modified natural frequency and damping ratio that account for the electromechanical coupling. The voltage and the harvested power are then obtained by relating them directly to the mechanical displacement. We validate the proposed analysis by comparing its solution including the tip displacement and harvested power with those of numerical simulations of the governing equations. To demonstrate the generality of the proposed approach, we consider the cases of base excitation, galloping, and autoparametric vibration. The model proposed in this study simplifies the electromechanical coupling problem for practical applications of cantilever-beam piezoelectric energy harvesting systems.

  6. Energy Harvesting By Optimized Piezo Transduction Mechanism

    OpenAIRE

    Boban, Bijo; Babu, S. K. Suresh; 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 energ...

  7. 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.

  8. 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.

  9. 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

  10. 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...

  11. Security challenges for energy-harvesting wireless sensor networks

    DEFF Research Database (Denmark)

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

    2012-01-01

    a new take in this topic. Traditional solutions may not work in this new field. Brand new challenges and threats may arise and new solutions have to be designed. In this paper we present a taxonomy of attacks, focusing on how they change in the energy harvesting scenario compared to regular sensor...

  12. Energy harvesting for the implantable biomedical devices: issues and challenges.

    Science.gov (United States)

    Hannan, Mahammad A; Mutashar, Saad; Samad, Salina A; Hussain, Aini

    2014-01-01

    The development of implanted devices is essential because of their direct effect on the lives and safety of humanity. This paper presents the current issues and challenges related to all methods used to harvest energy for implantable biomedical devices. The advantages, disadvantages, and future trends of each method are discussed. The concept of harvesting energy from environmental sources and human body motion for implantable devices has gained a new relevance. In this review, the harvesting kinetic, electromagnetic, thermal and infrared radiant energies are discussed. Current issues and challenges related to the typical applications of these methods for energy harvesting are illustrated. Suggestions and discussion of the progress of research on implantable devices are also provided. This review is expected to increase research efforts to develop the battery-less implantable devices with reduced over hole size, low power, high efficiency, high data rate, and improved reliability and feasibility. Based on current literature, we believe that the inductive coupling link is the suitable method to be used to power the battery-less devices. Therefore, in this study, the power efficiency of the inductive coupling method is validated by MATLAB based on suggested values. By further researching and improvements, in the future the implantable and portable medical devices are expected to be free of batteries. PMID:24950601

  13. Metamaterials-based enhanced energy harvesting: A review

    International Nuclear Information System (INIS)

    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.

  14. Energy harvesting for the implantable biomedical devices: issues and challenges

    Science.gov (United States)

    2014-01-01

    The development of implanted devices is essential because of their direct effect on the lives and safety of humanity. This paper presents the current issues and challenges related to all methods used to harvest energy for implantable biomedical devices. The advantages, disadvantages, and future trends of each method are discussed. The concept of harvesting energy from environmental sources and human body motion for implantable devices has gained a new relevance. In this review, the harvesting kinetic, electromagnetic, thermal and infrared radiant energies are discussed. Current issues and challenges related to the typical applications of these methods for energy harvesting are illustrated. Suggestions and discussion of the progress of research on implantable devices are also provided. This review is expected to increase research efforts to develop the battery-less implantable devices with reduced over hole size, low power, high efficiency, high data rate, and improved reliability and feasibility. Based on current literature, we believe that the inductive coupling link is the suitable method to be used to power the battery-less devices. Therefore, in this study, the power efficiency of the inductive coupling method is validated by MATLAB based on suggested values. By further researching and improvements, in the future the implantable and portable medical devices are expected to be free of batteries. PMID:24950601

  15. 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

  16. 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

  17. Thermal energy harvesters with piezoelectric or electrostatic transducer

    Science.gov (United States)

    Prokaryn, Piotr; Domański, Krzysztof; Marchewka, Michał; Tomaszewski, Daniel; Grabiec, Piotr; Puscasu, Onoriu; Monfray, Stéphane; Skotnicki, Thomas

    2014-08-01

    This paper describes the idea of the energy harvester which converts thermal gradient present in environment into electricity. Two kinds of such devices are proposed and their prototypes are shown and discussed. The main parts of harvesters are bimetallic spring, piezoelectric transducer or electrostatic transducer with electret. The applied piezomembrane was commercial available product but electrets was made by authors. In the paper a fabrication procedure of electrets formed by the corona discharge process is described. Devices were compared in terms of generated power, charging current, and the voltage across a storage capacitor.

  18. 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

  19. Energy Harvesting for Aerospace Structural Health Monitoring Systems

    Science.gov (United States)

    Pearson, M. R.; Eaton, M. J.; Pullin, R.; Featherston, C. A.; Holford, K. M.

    2012-08-01

    Recent research into damage detection methodologies, embedded sensors, wireless data transmission and energy harvesting in aerospace environments has meant that autonomous structural health monitoring (SHM) systems are becoming a real possibility. The most promising system would utilise wireless sensor nodes that are able to make decisions on damage and communicate this wirelessly to a central base station. Although such a system shows great potential and both passive and active monitoring techniques exist for detecting damage in structures, powering such wireless sensors nodes poses a problem. Two such energy sources that could be harvested in abundance on an aircraft are vibration and thermal gradients. Piezoelectric transducers mounted to the surface of a structure can be utilised to generate power from a dynamic strain whilst thermoelectric generators (TEG) can be used to generate power from thermal gradients. This paper reports on the viability of these two energy sources for powering a wireless SHM system from vibrations ranging from 20 to 400Hz and thermal gradients up to 50°C. Investigations showed that using a single vibrational energy harvester raw power levels of up to 1mW could be generated. Further numerical modelling demonstrated that by optimising the position and orientation of the vibrational harvester greater levels of power could be achieved. However using commercial TEGs average power levels over a flight period between 5 to 30mW could be generated. Both of these energy harvesting techniques show a great potential in powering current wireless SHM systems where depending on the complexity the power requirements range from 1 to 180mW.

  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. 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.

  2. Energy harvesting with piezoelectric circular membrane under pressure loading

    International Nuclear Information System (INIS)

    This paper presents a comprehensive theoretical model for predicting the energy generating performance of an energy harvesting device that uses a piezoelectric circular membrane subject to pressure fluctuation. PVDF (polyvinylidene fluoride) film is adopted for the membrane. In order to predict the power generating performance due to stretching and bending of the membrane, the total stress on the membrane, rather than the stress at the center point of the circular membrane, is determined using the energy method. Analytical results indicate that the theoretically predicted generated power of the device under normal blood pressure variation is close to experimental results available in the literature. This comprehensive model provides a useful design tool during parameter optimization for energy harvesters that use piezoelectric circular membranes for a pressure fluctuating system. (paper)

  3. 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...

  4. Modeling a novel energy harvester working in Lame mode

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Zhuming; Mei, Jie [Multidisciplinary Nanotechnology Centre, College of Engineering, Swansea University, SA2 8PP (United Kingdom); Li, Lijie, E-mail: L.Li@swansea.ac.uk [Multidisciplinary Nanotechnology Centre, College of Engineering, Swansea University, SA2 8PP (United Kingdom)

    2012-04-30

    A new square shaped piezoelectric bimorph structure for energy scavenging purposes has been proposed and simulated. It is derived from theoretical analysis that the output power of the structure is proportional to the value of the resonant frequency. The device working in Lame mode has a much higher resonant frequency of 2.39 MHz than devices working in ordinary bending modes, which is expected to significantly increase the energy output of radioisotope power generators (RPGs). The results of static analysis and dynamic response show that output voltage is linear with the applied load; the output power is quadratic with the applied load. -- Highlights: ► We present a new mechanical to electrical energy harvester. ► The energy harvester is square shaped and operated in Lame mode. ► The proposed design has very high resonant frequency. ► It is expected the device has promising application in radioisotope power generators.

  5. 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.

  6. Energy harvesting techniques for autonomous WSNs-RFID with a focus on RF energy harvesting

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Ping

    2012-04-27

    Supply circuits that harvest energy from surrounding ambient or dedicated sources have drawn much interest recently for providing a possibility of energy-autonomy to the wireless sensing devices. The objective of this thesis is to optimize the power transfer efficiency of the RF/microwave energy transducers in WSN/RFID applications. For this purpose, analysis on the power utilization of the wireless devices at different working states has been done, which implies a space of improving the power transfer efficiency by employing a novel design concept in the RF/microwave energy transducers. In order to observe a deep insight of the charge-pump based energy transducer, an analytical derivation has been implemented based on a compact I/V model for MOSFET working in strong inversion and subthreshold regions. The derivation provides a mathematical direction for the impact of the power consumption of the wireless device on the input impedance of the charge-pump rectifier, which acts as a core element in the energy transducer. With expressing the input impedance of the rectifier into a shunt connection of a resistor and a capacitor, as the load current consumption reduces the shunt resistance increases dramatically while the shunt capacitance holds a relatively constant value. This work proposes a methodology of employing an adaptively adjusted matching network between the rectifier and the antenna in order to optimize the power transfer efficiency according to the instant power consumption of the wireless devices on different working states. For read-only wireless devices with no embedded batteries, like RFID transponders, a tiny storage capacitor of pico-farad which can be charged-up to a certain voltage in microseconds is usually employed as a DC supplier. During the communication between reader and transponder, the reader radiates RF power continuously to supply the transponder. Extra power supply is required to adjust the matching network electrically for optimal power

  7. MEMS Rotational Electret Energy Harvester for Human Motion

    Science.gov (United States)

    Nakano, J.; Komori, K.; Hattori, Y.; Suzuki, Y.

    2015-12-01

    This paper reports the development of MEMS rotational electret energy harvester (EH) for capturing kinetic energy of human motion. Optimal design method of rotational electret EH is proposed by considering both the rate of overlapping-area-change and the parasitic capacitance. A rotational MEMS electret EH with embedded ball bearing has been successfully developed. Up to 3.6 μW has been obtained at 1 rps rotation with an early prototype.

  8. 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

  9. 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.

  10. Broadband energy harvesting using acoustic black hole structural tailoring

    Science.gov (United States)

    Zhao, Liuxian; Conlon, Stephen C.; Semperlotti, Fabio

    2014-06-01

    This paper explores the concept of an acoustic black hole (ABH) as a main design framework for performing dynamic structural tailoring of mechanical systems for vibration energy harvesting applications. The ABH is an integral feature embedded in the host structure that allows for a smooth reduction of the phase velocity, theoretically approaching zero, while minimizing the reflected energy. This mechanism results in structural areas with high energy density that can be effectively exploited to develop enhanced vibration-based energy harvesting. Fully coupled electro-mechanical models of an ABH tapered structure with surface mounted piezo-transducers are developed to numerically simulate the response of the system to both steady state and transient excitations. The design performances are numerically evaluated using structural intensity data as well as the instantaneous voltage/power and energy output produced by the piezo-transducer network. Results show that the dynamically tailored structural design enables a drastic increase in the harvested energy as compared to traditional structures, both under steady state and transient excitation conditions.

  11. 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.

  12. Nonlinear optimization of acoustic energy harvesting using piezoelectric devices.

    Science.gov (United States)

    Lallart, Mickaeël; Guyomar, Daniel; Richard, Claude; Petit, Lionel

    2010-11-01

    In the first part of the paper, a single degree-of-freedom model of a vibrating membrane with piezoelectric inserts is introduced and is initially applied to the case when a plane wave is incident with frequency close to one of the resonance frequencies. The model is a prototype of a device which converts ambient acoustical energy to electrical energy with the use of piezoelectric devices. The paper then proposes an enhancement of the energy harvesting process using a nonlinear processing of the output voltage of piezoelectric actuators, and suggests that this improves the energy conversion and reduces the sensitivity to frequency drifts. A theoretical discussion is given for the electrical power that can be expected making use of various models. This and supporting experimental results suggest that a nonlinear optimization approach allows a gain of up to 10 in harvested energy and a doubling of the bandwidth. A model is introduced in the latter part of the paper for predicting the behavior of the energy-harvesting device with changes in acoustic frequency, this model taking into account the damping effect and the frequency changes introduced by the nonlinear processes in the device. PMID:21110569

  13. A miniature airflow energy harvester from piezoelectric materials

    Science.gov (United States)

    Sun, H.; Zhu, D.; White, N. M.; Beeby, S. P.

    2013-12-01

    This paper describes design, simulation, fabrication, and testing of a miniature wind energy harvester based on a flapping cantilevered piezoelectric beam. The wind generator is based on oscillations of a cantilever that faces the direction of the airflow. The oscillation is amplified by interactions between an aerofoil attached on the cantilever and a bluff body placed in front of the aerofoil. A piezoelectric transducer with screen printed PZT materials is used to extract electrical energy. To achieve the optimum design of the harvester, both computational simulations and experiments have been carried out to investigate the structure. A prototype of the wind harvester, with the volume of 37.5 cm3 in total, was fabricated by thick-film screen printing technique. Wind tunnel test results are presented to determine the optimum structure and to characterize the performance of the harvester. The optimized device finally achieved a working wind speed range from 1.5 m/s to 8 m/s. The power output was ranging from 0.1 to 0.86 μW and the open-circuit output voltage was from 0.5 V to 1.32 V.

  14. Enhance piezoelectric energy harvesting by stiffness compensation using magnetic effect

    Science.gov (United States)

    Xu, Jiawen; Tang, J.

    2013-04-01

    Piezoelectric transducers are widely employed in vibration-based energy harvesting schemes. The efficiency of piezoelectric transducers fundamentally hinges upon the electro-mechanical coupling effect. While at the material level such coupling is decided by material property, at the device level it is possible to vary and improve the energy conversion capability between the electrical and mechanical regimes by a variety of means. In this research, a new approach of compensating the effective flexibility of piezoelectric transducers by using non-contact magnetic effect is explored. It is shown that properly configured and positioned magnet arrays can induce approximately linear attraction force that can improve the electro-mechanical coupling of the piezoelectric energy harvester. Analytical and experimental studies are carried out to demonstrate the enhancement.

  15. 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.

  16. Structures, systems and methods for harvesting energy from electromagnetic radiation

    Energy Technology Data Exchange (ETDEWEB)

    Novack, Steven D. (Idaho Falls, ID); Kotter, Dale K. (Shelley, ID); Pinhero, Patrick J. (Columbia, MO)

    2011-12-06

    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. Structures, systems and methods for harvesting energy from electromagnetic radiation

    Science.gov (United States)

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

    2011-12-06

    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.

  18. Characterization of a rotary hybrid multimodal energy harvester

    Science.gov (United States)

    Larkin, Miles R.; Tadesse, Yonas

    2014-04-01

    In this study, experimental characterizations of a new hybrid energy harvesting device consisting of piezoelectric and electromagnetic transducers are presented. The generator, to be worn on the legs or arms of a person, harnesses linear motion and impact forces from human motion to generate electrical energy. The device consists of an unbalanced rotor made of three piezoelectric beams which have permanent magnets attached to the ends. Impact forces cause the beams to vibrate, generating a voltage across their electrodes and linear motion causes the rotor to spin. As the rotor spins, the magnets pass over ten electromagnetic coils mounted to the base, inducing a current through the wire. Several design related issues were investigated experimentally in order to optimize the hybrid device for maximum power generation. Further experiments were conducted on the system to characterize the energy harvesting capabilities of the device, all of which are presented in this study.

  19. Energy harvesting efficiency of piezoelectric flags in axial flows

    CERN Document Server

    Michelin, Sebastien

    2012-01-01

    Self-sustained oscillations resulting from fluid-solid instabilities, such as the flutter of a flexible flag in axial flow, can be used to harvest energy if one is able to convert the solid energy into electricity. Here, this is achieved using piezoelectric patches attached to the surface of the flag that convert the solid deformation into an electric current powering purely resistive output circuits. Nonlinear numerical simulations in the slender-body limit, based on an explicit description of the coupling between the fluid-solid and electric systems, are used to determine the harvesting efficiency of the system, namely the fraction of the flow kinetic energy flux effectively used to power the output circuit, and its evolution with the system's parameters. The role of the tuning between the characteristic frequencies of the fluid-solid and electric systems is emphasized, as well as the critical impact of the piezoelectric coupling intensity. High fluid loading, classically associated with destabilization by ...

  20. Structural modelling of a compliant flexure flow energy harvester

    Science.gov (United States)

    Chatterjee, Punnag; Bryant, Matthew

    2015-09-01

    This paper presents the concept of a flow-induced vibration energy harvester based on a one-piece compliant flexure structure. This energy harvester utilizes the aeroelastic flutter phenomenon to convert flow energy to structural vibrational energy and to electrical power output through piezoelectric transducers. This flexure creates a discontinuity in the structural stiffness and geometry that can be used to tailor the mode shapes and natural frequencies of the device to the desired operating flow regime while eliminating the need for discrete hinges that are subject to fouling and friction. An approximate representation of the flexure rigidity is developed from the flexure link geometry, and a model of the complete discontinuous structure and integrated flexure is formulated based on the transfer matrix method. The natural frequencies and mode shapes predicted by the model are validated using finite element simulations and are shown to be in close agreement. A proof-of-concept energy harvester incorporating the proposed flexure design has been fabricated and investigated in wind tunnel testing. The aeroelastic modal convergence, critical flutter wind speed, power output and limit cycle behavior of this device is experimentally determined and discussed.

  1. 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.

  2. Improving an energy harvesting device for railroad safety applications

    Science.gov (United States)

    Pourghodrat, Abolfazl; Nelson, Carl A.; Phillips, Kyle J.; Fateh, Mahmood

    2011-03-01

    Due to hundreds of fatalities annually at unprotected railroad crossings (mostly because of collisions with passenger vehicles and derailments resulting from improperly maintained tracks and mechanical failures), supplying a reliable source of electrical energy to power crossing lights and distributed sensor networks is essential to improve safety. With regard to the high cost of electrical infrastructure for railroad crossings in remote areas and the lack of reliability and robustness of solar and wind energy solutions, development of alternative energy harvesting devices is of interest. In this paper, improvements to a mechanical energy harvesting device are presented. The device scavenges electrical energy from deflection of railroad track due to passing railcar traffic. It is mounted to and spans two rail ties and converts and magnifies the track's entire upward and downward displacement into rotational motion of a PMDC generator. The major improvements to the new prototype include: harvesting power from upward displacement in addition to downward, changing the gearing and generator in order to maximize power production capacity for the same shaft speed, and improving the way the system is stabilized for minimizing lost motion. The improved prototype was built, and simulations and tests were conducted to quantify the effects of the improvements.

  3. Nonmonotonic energy harvesting efficiency in biased exciton chains.

    Science.gov (United States)

    Vlaming, S M; Malyshev, V A; Knoester, J

    2007-10-21

    We theoretically study the efficiency of energy harvesting in linear exciton chains with an energy bias, where the initial excitation is taking place at the high-energy end of the chain and the energy is harvested (trapped) at the other end. The efficiency is characterized by means of the average time for the exciton to be trapped after the initial excitation. The exciton transport is treated as the intraband energy relaxation over the states obtained by numerically diagonalizing the Frenkel Hamiltonian that corresponds to the biased chain. The relevant intraband scattering rates are obtained from a linear exciton-phonon interaction. Numerical solution of the Pauli master equation that describes the relaxation and trapping processes reveals a complicated interplay of factors that determine the overall harvesting efficiency. Specifically, if the trapping step is slower than or comparable to the intraband relaxation, this efficiency shows a nonmonotonic dependence on the bias: it first increases when introducing a bias, reaches a maximum at an optimal bias value, and then decreases again because of dynamic (Bloch) localization of the exciton states. Effects of on-site (diagonal) disorder, leading to Anderson localization, are addressed as well. PMID:17949203

  4. 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.

  5. 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...... strategies and compare the slot- with the frame-based model in the case of an errorless transmission channel. Additionally, for the slot-based model and channel with errors, we provide a new proof of the capacity achieved by the save-and-transmit scheme....

  6. 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.

  7. Feasibility of Energy Harvesting Using a Piezoelectric Tire

    Science.gov (United States)

    Malotte, Christopher

    While the piezoelectric effect has been around for some time, it has only recently caught interest as a potential sustainable energy harvesting device. Piezoelectric energy harvesting has been developed for shoes and panels, but has yet to be integrated into a marketable bicycle tire. For this thesis, the development and feasibility of a piezoelectric tire was done. This includes the development of a circuit that incorporates piezoceramic elements, energy harvesting circuitry, and an energy storage device. A single phase circuit was designed using an ac-dc diode rectifier. An electrolytic capacitor was used as the energy storage device. A financial feasibility was also done to determine targets for manufacturing cost and sales price. These models take into account market trends for high performance tires, economies of scale, and the possibility of government subsidies. This research will help understand the potential for the marketability of a piezoelectric energy harvesting tire that can create electricity for remote use. This study found that there are many obstacles that must be addressed before a piezoelectric tire can be marketed to the general public. The power output of this device is minuscule compared to an alkaline battery. In order for this device to approach the power output of an alkaline battery the weight of the device would also become an issue. Additionally this device is very costly compared to the average bicycle tire. Lastly, this device is extreme fragile and easily broken. In order for this device to become marketable the issues of power output, cost, weight, and durability must all be successfully overcome.

  8. 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.)

  9. 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

  10. Acoustic energy harvesting using an electromechanical Helmholtz resonator.

    Science.gov (United States)

    Liu, Fei; Phipps, Alex; Horowitz, Stephen; Ngo, Khai; Cattafesta, Louis; Nishida, Toshikazu; Sheplak, Mark

    2008-04-01

    This paper presents the development of an acoustic energy harvester using an electromechanical Helmholtz resonator (EMHR). The EMHR consists of an orifice, cavity, and a piezoelectric diaphragm. Acoustic energy is converted to mechanical energy when sound incident on the orifice generates an oscillatory pressure in the cavity, which in turns causes the vibration of the diaphragm. The conversion of acoustic energy to electrical energy is achieved via piezoelectric transduction in the diaphragm of the EMHR. Moreover, the diaphragm is coupled with energy reclamation circuitry to increase the efficiency of the energy conversion. Lumped element modeling of the EMHR is used to provide physical insight into the coupled energy domain dynamics governing the energy reclamation process. The feasibility of acoustic energy reclamation using an EMHR is demonstrated in a plane wave tube for two power converter topologies. The first is comprised of only a rectifier, and the second uses a rectifier connected to a flyback converter to improve load matching. Experimental results indicate that approximately 30 mW of output power is harvested for an incident sound pressure level of 160 dB with a flyback converter. Such power level is sufficient to power a variety of low power electronic devices. PMID:18397006

  11. An electroactive polymer energy harvester for wireless sensor networks

    International Nuclear Information System (INIS)

    This paper reports the design, fabrication, and testing of a soft electroactive polymer power generator that has a volume of 1cm3. The generator provides an opportunity to harvest energy from environmental sources to power wireless sensor networks because it can harvest from low frequency motions, is compact, and lightweight. Electroactive polymers are highly stretchable variable capacitors. Electrical energy is produced when the deformation of a stretched, charged electroactive polymer is relaxed; like-charges are compressed together and opposite-charges are pushed apart, resulting in an increased voltage. Although electroactive polymers have impressively displayed energy densities as high as 550 mJ/g, they have been based on films with thicknesses of tens to hundreds of micrometers, thus a generator covering a large area would be required to provide useful power. Energy harvesters covering large areas are inconvenient to deploy in a wireless sensor network with a large number of nodes, so a generator that is compact in all three dimensions is required. In this work we fabricated a generator that can fit within a 11×11×9 mm envelope by stacking 42, 11mm diameter generator films on top of each other. When compressed cyclically at a rate of 0.5 Hz our generator produced 300 uW of power which is a sufficient amount of power for a low power wireless sensor node. The combination of our generator's small form factor and ability to harvest useful energy from low frequency motions provides an opportunity to deploy large numbers of wireless sensor nodes without the need for periodic, costly battery replacement

  12. An electroactive polymer energy harvester for wireless sensor networks

    Science.gov (United States)

    McKay, T. G.; Rosset, S.; Anderson, I. A.; Shea, H.

    2013-12-01

    This paper reports the design, fabrication, and testing of a soft electroactive polymer power generator that has a volume of 1cm3. The generator provides an opportunity to harvest energy from environmental sources to power wireless sensor networks because it can harvest from low frequency motions, is compact, and lightweight. Electroactive polymers are highly stretchable variable capacitors. Electrical energy is produced when the deformation of a stretched, charged electroactive polymer is relaxed; like-charges are compressed together and opposite-charges are pushed apart, resulting in an increased voltage. Although electroactive polymers have impressively displayed energy densities as high as 550 mJ/g, they have been based on films with thicknesses of tens to hundreds of micrometers, thus a generator covering a large area would be required to provide useful power. Energy harvesters covering large areas are inconvenient to deploy in a wireless sensor network with a large number of nodes, so a generator that is compact in all three dimensions is required. In this work we fabricated a generator that can fit within a 11×11×9 mm envelope by stacking 42, 11mm diameter generator films on top of each other. When compressed cyclically at a rate of 0.5 Hz our generator produced 300 uW of power which is a sufficient amount of power for a low power wireless sensor node. The combination of our generator's small form factor and ability to harvest useful energy from low frequency motions provides an opportunity to deploy large numbers of wireless sensor nodes without the need for periodic, costly battery replacement.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. Fabrication and testing of an energy-harvesting hydraulic damper

    Science.gov (United States)

    Li, Chuan; Tse, Peter W.

    2013-06-01

    Hydraulic dampers are widely used to dissipate energy during vibration damping. In this paper, an energy-harvesting hydraulic damper is proposed for collecting energy while simultaneously damping vibration. Under vibratory excitation, the flow of hydraulic oil inside the cylinder of the damper is converted into amplified rotation via a hydraulic motor, whose output shaft is connected to an electromagnetic generator capable of harvesting a large amount of energy. In this way, the vibration is damped by both oil viscosity and the operation of an electrical mechanism. An electromechanical model is presented to illustrate both the electrical and mechanical responses of the system. A three-stage identification approach is introduced to facilitate the model parameter identification using cycle-loading experiments. A prototype device is developed and characterized in a test rig. The maximum power harvested during the experiments was 435.1 W (m s-1)-1, using a predefined harmonic excitation with an amplitude of 0.02 m, a frequency of 0.8 Hz, and an optimal resistance of 2 Ω. Comparison of the experimental and computational results confirmed the effectiveness of both the electromechanical model and the three-stage identification approach in realizing the proposed design.

  18. 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

    2016-01-01

    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. PMID:27043559

  19. 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.

  20. 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

    2016-01-01

    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. PMID:27043559

  1. 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

  2. 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.

  3. 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.

  4. 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. PMID:26280407

  5. An Exact Analytical Solution to Exponentially Tapered Piezoelectric Energy Harvester

    Directory of Open Access Journals (Sweden)

    H. Salmani

    2015-01-01

    Full Text Available It has been proven that tapering the piezoelectric beam through its length optimizes the power extracted from vibration based energy harvesting. This phenomenon has been investigated by some researchers using semianalytical, finite element and experimental methods. In this paper, an exact analytical solution is presented to calculate the power generated from vibration of exponentially tapered unimorph and bimorph with series and parallel connections. The mass normalized mode shapes of the exponentially tapered piezoelectric beam with tip mass are implemented to transfer the proposed electromechanical coupled equations into modal coordinates. The steady states harmonic solution results are verified both numerically and experimentally. Results show that there exist values for tapering parameter and electric resistance in a way that the output power per mass of the energy harvester will be maximized. Moreover it is concluded that the electric resistance must be higher than a specified value for gaining more power by tapering the beam.

  6. A compact architecture for passively-switched energy harvesters

    Science.gov (United States)

    Liu, Tian; Livermore, Carol

    2015-12-01

    This paper presents the design and experimental characterization of a compact parallel-beam architecture for low-frequency energy harvesters that switch passively among dynamical modes to extend their operational range. Two beams interact to generate power; a driving beam couples into low frequency vibrations, and a higher frequency generating beam outputs power upon impact by the driving beam. The system switches between modes in which the driving beam bounces off the generating beam (coupled motion) and modes in which the driving beam passes the generating beam (plucked motion). The compact structure is realized by mounting the generating beam within a U-shaped driving beam on a single support. A flexible tip is mounted inside the driving beam's U shape to enable robust interactions. This new architecture reduces system volume by 80% compared with an earlier model that has the same resonance frequency, but it also changes the flexible tip's role in the contact dynamics. The flexible tip is experimentally tailored to optimize performance. The harvester generates power over the measured range of acceleration from 0.2 g to 2 g and driving frequency from 5 Hz to 20 Hz. With one tip design, the harvester offers peak power of 0.267 mW with plucked operation covering 32% of the tested range. With a second tip design, the harvester offers a lower peak power of 0.036 mW with plucked operation covering 73% of the tested range.

  7. 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

  8. 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...

  9. Human motion energy harvesting using a piezoelectric MFC patch.

    Science.gov (United States)

    Bassani, Giulia; Filippeschi, Alessandro; Ruffaldi, Emanuele

    2015-01-01

    The improvements in efficiency of electronic components and miniaturization is quickly pushing wearable devices. Kinetic human energy harvesting is a way to power these components reducing the need of batteries replacement since walking or running is how humans already expend much of their daily energy. This work explores the case of kinetic energy from bending of a piezoelectric patch. For assessing the quality of the system, a testing setup has been designed and controlled by means of knee joint recordings obtained from a large motion dataset. The promising result of the chosen patch is an output power of 2.6μW associated to a run activity. PMID:26737431

  10. Infrared Solar Energy Harvesting using Nano-Rectennas

    OpenAIRE

    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 na...

  11. Steady-State Oscillations in Resonant Electrostatic Vibration Energy Harvesters

    OpenAIRE

    Blokhina, Elena; Galayko, Dimitri; Basset, Philippe; Feely, Orla

    2013-01-01

    In this paper, we present a formal analysis and description of the steady-state behavior of an electrostatic vibration energy harvester operating in constant-charge mode and using different types of electromechanical transducers. The method predicts parameter values required to start oscillations, allows a study of the dynamics of the transient process, and provides a rigorous description of the system, necessary for further investigation of the related nonlinear phenomena and for the optimis...

  12. 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

  13. 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

  14. Energy harvesting for microelectronics. Energy efficient and energy autarkic solutions for wireless sensor systems; Energy Harvesting fuer Mikroelektronik. Energieeffiziente und -autarke Loesungen fuer drahtlose Sensorsysteme

    Energy Technology Data Exchange (ETDEWEB)

    Dembowski, Klaus

    2011-07-01

    Energy efficiency and renewable energy fields promise to be sustainable fields of growth in the coming years. In the case of micro energy harvesting relatively small amounts of energy is 'harvested' from the ambient energy in order to enable energy-efficient and self-sufficient solutions in the field of microelectronics. The book under consideration provides: (a) The necessary fundamentals concerning energy production (e.g., thermal generators, piezoelectric transducers, energy from RF radiation); (b) Energy storage as with batteries, capacitors, voltage converters and converter circuits; (c) Information to sensor/actuator system (types, signal conditioning, signal conversion); (d) Suitable microcontrollers and power saving mechanisms; (e) Wireless communication (transponder systems, wireless standards). In addition, application examples for system monitoring, building automation or in the medical technology are presented in detail.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. Suspended electrodes for reducing parasitic capacitance in electret energy harvesters

    International Nuclear Information System (INIS)

    MEMS electret energy harvesting devices are believed promising to replace coin batteries in low-power consumption electronics such as wireless sensor nodes and wearable devices. However, the parasitic capacitance of the interdigital electrodes imposes significant restrictions to enhancing the power output. To address this issue, this paper presents a novel low-k electrode structure based on a new model of the parasitic capacitance in electret energy harvesters. By employing the trench-filled parylene technology, metal electrodes suspended with deep honeycomb parylene structures have been prototyped. Thanks to the high air volume fraction (76%) of the honeycomb parylene structure, the effective relative permittivity κeff surrounding the electrodes is reduced to as low as 1.8 when the air gap is 90 µm between the electret surface and the counter electrode. As a result, the parasitic capacitance in the electret energy harvester is decreased by 36% compared with that of electrodes on glass substrates, which leads to a 35% increase in the power output. (paper)

  1. 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.

  2. 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.

  3. Power performance improvements for high pressure ripple energy harvesting

    International Nuclear Information System (INIS)

    A hydraulic pressure energy harvester (HPEH) device, which utilizes a housing in order to isolate a piezoelectric stack from the hydraulic fluid via a mechanical interface, generates power by converting the dynamic pressure within the system into electricity. Energy harvester prototypes were designed for generating low-power electricity from pressure ripples. These devices generate low-power electricity from off-resonance dynamic pressure excitation. The power produced per volume of piezoelectric material is analyzed to increase the power density; this is accomplished through evaluating piezoelectric stack characteristics, adding an inductor to the system circuit, and solving for optimal loading in order to achieve maximum power output. The prototype device utilizes a piezoelectric stack with high overall capacitance, which allows for inductance matching without using an active circuit. This work presents an electromechanical model and the experimental results of the HPEH devices using a parallel connection of inductive and resistive loads as the energy harvesting circuit. A non-ideal inductive load case is also considered and successfully modeled by accounting for the parasitic resistance of the inductive load. Various HPEH prototypes are fabricated, modeled, and compared in terms of their normalized power density levels, and milli-Watt level average power generation is demonstrated. The highest power density is reported for the single-crystal HPEH prototype. (paper)

  4. Hydraulic pressure energy harvester enhanced by Helmholtz resonator

    Science.gov (United States)

    Skow, Ellen; Koontz, Zachary; Cunefare, Kenneth; Erturk, Alper

    2015-04-01

    Hydraulic pressure energy harvesters (HPEH) are devices that convert the dynamic pressure within hydraulic systems into usable electrical power through axially loaded piezoelectric stacks excited off-resonance by the fluid. Within hydraulic systems, the dominant frequency is typically a harmonic of the pump operating frequency. The pressure fluctuations coupled with the piezoelectric stack can be amplified by creating a housing design that includes a Helmholtz resonator tuned to the dominant frequency of the fluid excitation. A Helmholtz resonator is an acoustic device that consists of a cavity coupled to a fluid medium via a neck, or in this case a port connection to the fluid flow, that acts as an amplifier when within the bandwidth of its resonance. The implementation of a piezoelectric stack within the HPEH allows for a Helmholtz resonator to be included within the fluidic environment despite the significantly higher than air static pressures typical of fluid hydraulic systems (on the order of one to tens of MPa). The resistive losses within the system, such as from energy harvesting and viscous losses, can also be used to increase the bandwidth of the resonance; thus increasing the utility of the device. This paper investigates the design, modeling, and performance of hydraulic pressure energy harvesters utilizing a Helmholtz resonator design.

  5. Power performance improvements for high pressure ripple energy harvesting

    Science.gov (United States)

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

    2014-10-01

    A hydraulic pressure energy harvester (HPEH) device, which utilizes a housing in order to isolate a piezoelectric stack from the hydraulic fluid via a mechanical interface, generates power by converting the dynamic pressure within the system into electricity. Energy harvester prototypes were designed for generating low-power electricity from pressure ripples. These devices generate low-power electricity from off-resonance dynamic pressure excitation. The power produced per volume of piezoelectric material is analyzed to increase the power density; this is accomplished through evaluating piezoelectric stack characteristics, adding an inductor to the system circuit, and solving for optimal loading in order to achieve maximum power output. The prototype device utilizes a piezoelectric stack with high overall capacitance, which allows for inductance matching without using an active circuit. This work presents an electromechanical model and the experimental results of the HPEH devices using a parallel connection of inductive and resistive loads as the energy harvesting circuit. A non-ideal inductive load case is also considered and successfully modeled by accounting for the parasitic resistance of the inductive load. Various HPEH prototypes are fabricated, modeled, and compared in terms of their normalized power density levels, and milli-Watt level average power generation is demonstrated. The highest power density is reported for the single-crystal HPEH prototype.

  6. State of the art in acoustic energy harvesting

    International Nuclear Information System (INIS)

    For portable and embedded smart, wireless electronic systems, energy harvesting from the ambient energy sources has gained immense interest in recent years. Several ambient energies exist in the environment of wireless sensor nodes (WSNs) that include thermal, solar, vibration and acoustic energy. This paper presents the recent development in the field of acoustic energy harvesters (AEHs). AEHs convert the acoustic energy into useful electrical energy for the operation of autonomous wireless sensors. Mainly, two types of AEHs (electromagnetic and piezoelectric based) have been developed and reported in literature. The power produced by the reported piezoelectric AEHs ranges from 0.68 pW to 30 mW; however, the power generation of the developed electromagnetic AEHs is in the range of 1.5–1.96 mW. The overall size of most of the developed piezoelectric and electromagnetic AEHs are quite comparable and in millimeter scale. The resonant frequencies of electromagnetic AEHs are on the lower side (143–470 Hz), than that of piezoelectric AEHs (146 Hz–16.7 kHz). (topical review)

  7. 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.

  8. 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. PMID:27167321

  9. 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.

  10. 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

  11. 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.

  12. 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.

  13. 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.

  14. Effect of electrode configurations on piezoelectric vibration energy harvesting performance

    Science.gov (United States)

    Kim, Miso; Dugundji, John; Wardle, Brian L.

    2015-04-01

    Piezoelectric vibration energy harvesting is an attractive technology for self-powered wireless sensor networks because of the potential to deliver power to the sensor nodes from mechanical vibration sources in the surrounding medium. Systematic device designs are required in order to increase performance along with materials development of high piezoelectric coefficients and design of circuits with high power transfer efficiency. In this work, we present refined structural and electrical modeling of interdigitated electrodes (IDEs) for piezoelectric vibration energy harvesting, followed by parametric case studies on MEMS devices. Differences in geometric parameters including the size of the electrode and the number of IDE fingers for given device dimensions lead to substantial changes in harvesting performance such as capacitance, system coupling, voltage and power. When compared with parallel plate electrodes, use of IDEs results in much higher voltage generation by a factor of ten times while similar power levels are observed for both {3-1} and {3-3} configurations at optimal electrical loading conditions.

  15. Acrylic interpenetrating polymer network dielectric elastomers for energy harvesting

    Science.gov (United States)

    Brochu, Paul; Niu, Xiaofan; Pei, Qibing

    2011-04-01

    Dielectric elastomer energy harvesters are an emerging technology that promise high power density, low cost, scalability, and the capability of fitting niche markets that have yet to be exploited. To date, materials issues that limit their overall performance have hampered the full potential of these devices. In order to supplant existing technologies, even in niche markets, dielectric elastomer generators must increase their reliability and energy density. Previous work has indicated that stiffer elastomers should be capable of higher energy densities; the increased stiffness of the elastomer films should results in lower Maxwell pressure induced strains, and thus allow the elastomer to relax further, resulting in a larger swing in capacitance and larger energy gains. In this paper we examine the use of VHB-based acrylic interpenetrating polymer network dielectric elastomers with a trimethylolpropane trimethacrylate additive network for energy harvesting purposes. We test films with varying additive content and compare their performance with highly prestrained VHB acrylic elastomers. We show that by increasing additive content, Maxwell induced strains can be suppressed and larger energy gains can be achieved at higher bias fields. Moreover, the introduction of the additive network stabilizes the highly prestrained acrylic elastomers mechanically, thereby increasing their mechanical robustness. However, the interpenetrating polymer network films suffer from an increase in viscoelastic behavior that hinders their overall performance.

  16. 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.

  17. Complementary split ring resonator arrays for electromagnetic energy harvesting

    Science.gov (United States)

    Alavikia, Babak; Almoneef, Thamer S.; Ramahi, Omar M.

    2015-07-01

    This work demonstrates the viability of Ground-backed Complementary Split-Ring Resonator (G-CSRR) arrays with significant power conversion efficiency and bandwidth enhancement in comparison to the technology used in current electromagnetic energy harvesting systems. Through numerical full-wave analysis, we demonstrated correlation between either the resonance frequency or the input impedance of G-CSRR cells with the periodicity of the array. A comparative study of power harvesting efficiency through numerical analysis and laboratory measurement was presented where an array of G-CSRRs is compared to an array of microstrip patch antennas. We demonstrated that a G-CSRR array yields power conversion efficiency of 92%, which represents a significant improvement in comparison to the single G-CSRR reported in our earlier work.

  18. 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.

  19. Micro rectennas: Brownian ratchets for thermal-energy harvesting

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Y.; Powell, C. V.; Balocco, C., E-mail: claudio.balocco@durham.ac.uk [School of Engineering and Computing Sciences, Durham University, Durham DH1 3LE (United Kingdom); Song, A. M. [School of Electrical and Electronic Engineering, University of Manchester, Manchester M13 9PL (United Kingdom)

    2014-12-22

    We experimentally demonstrated the operation of a rectenna for harvesting thermal (blackbody) radiation and converting it into dc electric power. The device integrates an ultrafast rectifier, the self-switching nanodiode, with a wideband log-periodic spiral microantenna. The radiation from the thermal source drives the rectenna out of thermal equilibrium, permitting the rectification of the excess thermal fluctuations from the antenna. The power conversion efficiency increases with the source temperatures up to 0.02% at 973 K. The low efficiency is attributed mainly to the impedance mismatch between antenna and rectifier, and partially to the large field of view of the antenna. Our device not only opens a potential solution for harvesting thermal energy but also provides a platform for experimenting with Brownian ratchets.

  20. Nonlinear effects in electrostatic vibration energy harvesters: current progress and perspectives

    OpenAIRE

    Galayko, Dimitri; Blokhina, Elena

    2013-01-01

    In this review paper, we discuss the principles of electrostatic (capacitive) vibration energy harvesters and nonlinear techniques that can be applied to improve the performance of harvesters. Electrostatic vibration energy harvesters are devices that contain mechanical resonators driven by ambient vibrations and coupled with conditioning electronic circuits through a capacitive transducer. While the devices can be fabricated using MEMS technology and miniaturised, intern...

  1. 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.

  2. Acoustic metamaterials capable of both sound insulation and energy harvesting

    Science.gov (United States)

    Li, Junfei; Zhou, Xiaoming; Huang, Guoliang; Hu, Gengkai

    2016-04-01

    Membrane-type acoustic metamaterials are well known for low-frequency sound insulation. In this work, by introducing a flexible piezoelectric patch, we propose sound-insulation metamaterials with the ability of energy harvesting from sound waves. The dual functionality of the metamaterial device has been verified by experimental results, which show an over 20 dB sound transmission loss and a maximum energy conversion efficiency up to 15.3% simultaneously. This novel property makes the metamaterial device more suitable for noise control applications.

  3. 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

  4. 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

  5. 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.

  6. 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.

  7. Heat to electricity conversion by cold carrier emissive energy harvesters

    International Nuclear Information System (INIS)

    This paper suggests a method to convert heat to electricity by the use of devices called cold carrier emissive energy harvesters (cold carrier EEHs). The working principle of such converters is explained and theoretical power densities and efficiencies are calculated for ideal devices. Cold carrier EEHs are based on the same device structure as hot carrier solar cells, but works in an opposite way. Whereas a hot carrier solar cell receives net radiation from the sun and converts some of this radiative heat flow into electricity, a cold carrier EEH sustains a net outflux of radiation to the surroundings while converting some of the energy supplied to it into electricity. It is shown that the most basic type of cold carrier EEHs have the same theoretical efficiency as the ideal emissive energy harvesters described earlier by Byrnes et al. In the present work, it is also shown that if the emission from the cold carrier EEH originates from electron transitions across an energy gap where a difference in the chemical potential of the electrons above and below the energy gap is sustained, power densities slightly higher than those given by Byrnes et al. can be achieved

  8. 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.

  9. 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.

  10. Heat to electricity conversion by cold carrier emissive energy harvesters

    Energy Technology Data Exchange (ETDEWEB)

    Strandberg, Rune [Department of Engineering Sciences, University of Agder, Jon Lilletuns vei 9, 4879 Grimstad (Norway)

    2015-12-07

    This paper suggests a method to convert heat to electricity by the use of devices called cold carrier emissive energy harvesters (cold carrier EEHs). The working principle of such converters is explained and theoretical power densities and efficiencies are calculated for ideal devices. Cold carrier EEHs are based on the same device structure as hot carrier solar cells, but works in an opposite way. Whereas a hot carrier solar cell receives net radiation from the sun and converts some of this radiative heat flow into electricity, a cold carrier EEH sustains a net outflux of radiation to the surroundings while converting some of the energy supplied to it into electricity. It is shown that the most basic type of cold carrier EEHs have the same theoretical efficiency as the ideal emissive energy harvesters described earlier by Byrnes et al. In the present work, it is also shown that if the emission from the cold carrier EEH originates from electron transitions across an energy gap where a difference in the chemical potential of the electrons above and below the energy gap is sustained, power densities slightly higher than those given by Byrnes et al. can be achieved.

  11. Interaction of turbulence with flexible beams in fluidic energy harvesting

    Science.gov (United States)

    Danesh Yazdi, Amir Hossein

    Advances in the development and fabrication of microelectronics have enhanced the energy efficiency of these devices to such an extent that they can now operate at very low power levels, typically on the order of a few microwatts or less. Batteries are primarily thought of as the most convenient source of power for electronic devices, but in instances where a device needs to be deployed in a difficult-to-access location such as under water, the added weight and especially maintenance of such a power source becomes costly. A solution that avoids this problem and is particularly attractive in a "deploy & forget" setting involves designing a device that continuously harvests energy from the surrounding environment. Piezoelectric energy harvesters, which employ the direct piezoelectric effect to convert mechanical strain into electrical energy, have garnered a great deal of attention in the literature. This work presents an overview of the experimental and analytical results related to fluidic energy extraction from vortex and turbulent flow using piezoelectric cantilever beams. In particular, the development of the FTGF (Fourier Transform-Green's Function) solution approach to the coupled, continuous electromechanical equations governing piezoelectric cantilever beams and the associated TFB (Train of Frozen Boxcars) method, which models the flow of vortices and turbulent eddies over the beams, is discussed. In addition, the behavior of fluidic energy harvesters in decaying isotropic, homogeneous grid turbulence generated by passive, semi-passive and active grids is examined and a novel grid-turbulence forcing model is introduced. An expression for the expected power output of the piezoelectric beam is obtained by utilizing this forcing function model in the single degree-of-freedom electromechanical equations. Furthermore, approximate, closed-form solutions to the theoretical expected power are derived from deterministic turbulence forcing models and are compared with

  12. 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

    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......) scheme of an industrial case study (IMR+) to a MAC scheme specifically designed for energy harvesting systems (ODMAC). Our analytical comparison shows the efficiency of the latter, as well as its ability to adapt to harvested ambient energy....

  13. Movers and Shakers: Kinetic Energy Harvesting for the Internet of Things

    OpenAIRE

    Gorlatova, Maria; Sarik, John; Grebla, Guy; Cong, Mina; Kymissis, Ioannis; Zussman, Gil

    2013-01-01

    Numerous energy harvesting wireless devices that will serve as building blocks for the Internet of Things (IoT) are currently under development. However, there is still only limited understanding of the properties of various energy sources and their impact on energy harvesting adaptive algorithms. Hence, we focus on characterizing the kinetic (motion) energy that can be harvested by a wireless node with an IoT form factor and on developing energy allocation algorithms for such nodes. In this ...

  14. 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.

  15. Energy Harvesting from Human Motion Using Footstep-Induced Airflow

    Science.gov (United States)

    Fu, H.; Xu, R.; Seto, K.; Yeatman, E. M.; Kim, S. G.

    2015-12-01

    This paper presents an unobtrusive in-shoe energy harvester converting foot-strike energy into electricity to power wearable or portable devices. An air-pumped turbine system is developed to address the issues of the limited vertical deformation of shoes and the low frequency of human motion that impede harvesting energy from this source. The air pump is employed to convert the vertical foot-strike motion into airflow. The generated airflow passes through the miniaturized wind turbine whose transduction is realized by an electromagnetic generator. Energy is extracted from the generator with a higher frequency than that of footsteps, boosting the output power of the device. The turbine casing is specifically designed to enable the device to operate continuously with airflow in both directions. A prototype was fabricated and then tested under different situations. A 6 mW peak power output was obtained with a 4.9 Ω load. The achievable power from this design was estimated theoretically for understanding and further improvement.

  16. 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.

  17. Efficiency enhancement of a cantilever-based vibration energy harvester.

    Science.gov (United States)

    Kubba, Ali E; Jiang, Kyle

    2013-01-01

    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 (V(ave)), and average normal strain in the piezoelectric transducer (ε(ave)) 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). PMID:24366177

  18. Rotational piezoelectric wind energy harvesting using impact-induced resonance

    Science.gov (United States)

    Yang, Ying; Shen, Qinlong; Jin, Jiamei; Wang, Yiping; Qian, Wangjie; Yuan, Dewang

    2014-08-01

    To improve the output power of a rotational piezoelectric wind energy harvester, impact-induced resonance is proposed to enable effective excitation of the piezoelectric cantilevers' vibration modes and obtain optimum deformation, which enhances the mechanical/electrical energy transformation. The impact force is introduced by forming a piezoelectric bimorph cantilever polygon that is fixed at the circumference of the rotating fan's internal surface. Elastic balls are placed inside the polygon. When wind rotates the device, the balls strike the piezoelectric cantilevers, and thus electricity is generated by the piezoelectric effect. The impact point is carefully chosen to use the first bending mode as much as possible, and thus maximize the harvesting efficiency. The design enables each bimorph to be struck in a similar area and every bimorph is struck in that area at different moments. As a result, a relatively stable output frequency can be obtained. The output frequency can also be changed by choosing different bimorph dimensions, which will also make the device simpler and the costs lower. A prototype piezoelectric energy harvester consisting of twelve piezoelectric cantilevers was constructed. The piezoelectric cantilevers were made from phosphor bronze, the lead zirconium titanate (PZT)-based bimorph cantilever had dimensions of 47 mm × 20 mm × 0.5 mm, and the elastic balls were made from steel with a diameter of 10 mm. The optimal DC output power was 613 μW across the 20 kΩ resistor at a rotation speed of 200 r/min with an inscribed circle diameter of 31 mm.

  19. 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.

  20. 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.

  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...... 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. Near-field thermodynamics and nanoscale energy harvesting

    Science.gov (United States)

    Latella, Ivan; Pérez-Madrid, Agustín; Lapas, Luciano C.; Rubi, J. Miguel

    2015-10-01

    We study the thermodynamics of near-field thermal radiation between two identical polar media at different temperatures. As an application, we consider an idealized energy harvesting process from sources at near room temperature at the nanoscale. We compute the maximum work flux that can be extracted from the radiation in the near-field regime and compare it with the corresponding maximum work flux in the blackbody regime. This work flux is considerably higher in the near-field regime. For materials that support surface phonon polaritons, explicit expressions for the work flux and an upper bound for the efficiency as functions of the surface wave frequency are obtained.

  4. Energy harvesting under excitation of clamped-clamped beam

    Science.gov (United States)

    Batra, Ashok; Alomari, Almuatasim; Aggarwal, Mohan; Bandyopadhyay, Alak

    2016-04-01

    In this article, a piezoelectric energy harvesting has been developed experimentally and theoretically based on Euler- Bernoulli Theory. A PVDF piezoelectric thick film has attached along of clamped-clamped beam under sinusoidal base excitation of shaker. The results showed a good agreement between the experimental and simulation of suggested model. The voltage output frequency response function (FRF), current FRF, and output power has been studied under short and open circuit conditions at first vibration mode. The mode shape of the clamped-clamped beam for first three resonance frequency has been modeled and investigated using COMSOL Multiphysics and MATLAB.

  5. 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.

  6. 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.

  7. 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.

  8. 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

  9. 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...

  10. 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

  11. 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...

  12. Optimization of an electret-based energy harvester

    CERN Document Server

    Boisseau, S; Sylvestre, A; 10.1088/0964-1726/19/7/075015

    2011-01-01

    Thanks to miniaturisation, it is today possible to imagine self-powered systems that use vibrations to produce their own electrical energy. Many energy-harvesting systems already exist. Some of them are based on the use of electrets: electrically charged dielectrics that can keep charges for years. This paper presents an optimisation of an existing system and proves that electret-based electrostatic energy scavengers can be excellent solutions to power microsystems even with low-level ambient vibrations. Thereby, it is possible to harvest up to 200\\muW with vibrations lower than 1G of acceleration (typically 50\\mumpp at 50Hz) using thin SiO2 electrets with an active surface of 1 cm^{2} and a mobile mass of 1g. This paper optimises such a system (geometric, electrostatic and mechanical parameters), using FEM (Finite Element Method) software (Comsol Multiphysics) and Matlab to compute the parameters and proves the importance of such an optimisation to build efficient systems. Finally, it shows that the use of e...

  13. 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.

  14. 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.

  15. 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.

  16. Energy Harvesting of a Flapping Airfoil in a Vortical Wake

    Science.gov (United States)

    Zheng, Z. Charlie; Wei, Zhenglun

    2014-11-01

    We study the response of a two-dimensional flapping airfoil in the wake downstream of an oscillating D-shape cylinder. The airfoil has either heaving or pitching motions. The leading edge vortex (LEV) and trailing edge vortex (TEV) of the airfoil play important roles in energy harvesting. Two major interaction modes between the airfoil and incoming vortices, the suppressing mode and the reinforcing mode, are identified. However, distinctions exist between the heaving and pitching motion in terms of their contributions to the interaction modes and the efficiency of the energy extraction. A potential theory and the related fluid dynamics analysis are developed to analytically demonstrate that the topology of the incoming vortices corresponding to the airfoil is the primary factor that determines the interaction modes. Finally, the trade-off between the input and the output is discussed. It is found that appropriate operational parameters for the heaving motion are preferable in order to preserve acceptable input power for energy harvesters, while appropriate parameters for the pitching motion are essential to achieve decent output power.

  17. 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. PMID:26903650

  18. 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.

  19. 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.

  20. A compact human-powered energy harvesting system

    International Nuclear Information System (INIS)

    This paper presents a fully functional, self-sufficient body-worn energy harvesting system for passively capturing energy from human motion, with the long-term vision of supplying power to portable, wearable, or even implanted electronic devices. The system requires no external power supplies and can bootstrap from zero-state-of-charge to generate electrical energy from walking, jogging and cycling; convert the induced ac voltage to a dc voltage; and then boost and regulate the dc voltage to charge a Li-ion-polymer battery. Tested under normal human activities (walking, jogging, cycling) when worn on different parts of the body, the 70 cm3 system is shown to charge a 3.7 V rechargeable battery at charge rates ranging from 33 μW to 234 μW

  1. 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.

  2. 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.

  3. 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.

  4. Copper and Zinc Oxide Composite Nanostructures for Solar Energy Harvesting

    Science.gov (United States)

    Wu, Fei

    Solar energy is a clean and sustainable energy source to counter global environmental issues of rising atmospheric CO2 levels and depletion of natural resources. To extract useful work from solar energy, silicon-based photovoltaic devices are extensively used. The technological maturity and the high quality of silicon (Si) make it a material of choice. However limitations in Si exist, ranging from its indirect band gap to low light absorption coefficient and energy and capital intensive crystal growth schemes. Therefore, alternate materials that are earth-abundant, benign and simpler to process are needed for developing new platforms for solar energy harvesting applications. In this study, we explore oxides of copper (CuO and Cu2O) in a nanowire morphology as alternate energy harvesting materials. CuO has a bandgap of 1.2 eV whereas Cu2O has a bandgap of 2.1 eV making them ideally suited for absorbing solar radiation. First, we develop a method to synthesize vertical, single crystalline CuO and Cu2O nanowires of ~50 microm length and aspect ratios of ~200. CuO nanowire arrays are synthesized by thermal oxidation of Cu foils. Cu2O nanowire arrays are synthesized by thermal reduction of CuO nanowires. Next, surface engineering of these nanowires is achieved using atomic layer deposition (ALD) of ZnO. By depositing 1.4 nm of ZnO, a highly defective surface is produced on the CuO nanowires. These defects are capable of trapping charge as is evident through persistent photoconductivity measurements of ZnO coated CuO nanowires. The same nanowires serve as efficient photocatalysts reducing CO2 to CO with a yield of 1.98 mmol/g-cat/hr. Finally, to develop a robust platform for flexible solar cells, a protocol to transfer vertical CuO nanowires inside flexible polydimethylsiloxane (PDMS) is demonstrated. Embedded CuO nanowires-ZnO pn junctions show a VOC of 0.4 V and a JSC of 10.4 microA/cm2 under white light illumination of 5.7 mW/cm2. Thus, this research provides broad

  5. 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.

  6. 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....

  7. 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.

  8. 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.

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

    Directory of Open Access Journals (Sweden)

    L. R. Corr

    2016-08-01

    Full Text Available 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.

  10. 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.

  11. Modeling coherent excitation energy transfer in photosynthetic light harvesting systems

    Science.gov (United States)

    Huo, Pengfei

    2011-12-01

    Recent non-linear spectroscopy experiments suggest the excitation energy transfer in some biological light harvesting systems initially occurs coherently. Treating such processes brings significant challenge for conventional theoretical tools that usually involve different approximations. In this dissertation, the recently developed Iterative Linearized Density Matrix (ILDM) propagation scheme, which is non-perturbative and non-Markovian is extended to study coherent excitation energy transfer in various light harvesting complexes. It is demonstrated that the ILDM approach can successfully describe the coherent beating of the site populations on model systems and gives quantitative agreement with both experimental results and the results of other theoretical methods have been developed recently to going beyond the usual approximations, thus providing a new reliable theoretical tool to study this phenomenon. This approach is used to investigate the excited energy transfer dynamics in various experimentally studied bacteria light harvesting complexes, such as Fenna-Matthews-Olsen (FMO) complex, Phycocyanin 645 (PC645). In these model calculations, quantitative agreement is found between computed de-coherence times and quantum beating pattens observed in the non-linear spectroscopy. As a result of these studies, it is concluded that the stochastic resonance behavior is important in determining the optimal throughput. To begin addressing possible mechanics for observed long de-coherence time, various models which include correlation between site energy fluctuations as well as correlation between site energy and inter-site coupling are developed. The influence of both types of correlation on the coherence and transfer rate is explored using with a two state system-bath hamiltonian parametrized to model the reaction center of Rhodobacter sphaeroides bacteria. To overcome the disadvantages of a fully reduced approach or a full propagation method, a brownian dynamics

  12. 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. .

  13. Thermoelectric energy harvesting for a solid waste processing toilet

    Science.gov (United States)

    Stokes, C. David; Baldasaro, Nicholas G.; Bulman, Gary E.; Stoner, Brian R.

    2014-06-01

    Over 2.5 billion people do not have access to safe and effective sanitation. Without a sanitary sewer infrastructure, self-contained modular systems can provide solutions for these people in the developing world and remote areas. Our team is building a better toilet that processes human waste into burnable fuel and disinfects the liquid waste. The toilet employs energy harvesting to produce electricity and does not require external electrical power or consumable materials. RTI has partnered with Colorado State University, Duke University, and Roca Sanitario under a Bill and Melinda Gates Foundation Reinvent the Toilet Challenge (RTTC) grant to develop an advanced stand-alone, self-sufficient toilet to effectively process solid and liquid waste. The system operates through the following steps: 1) Solid-liquid separation, 2) Solid waste drying and sizing, 3) Solid waste combustion, and 4) Liquid waste disinfection. Thermoelectric energy harvesting is a key component to the system and provides the electric power for autonomous operation. A portion of the exhaust heat is captured through finned heat-sinks and converted to electricity by thermoelectric (TE) devices to provide power for the electrochemical treatment of the liquid waste, pumps, blowers, combustion ignition, and controls.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. Nonlinear Dynamics of Pendulums System for Energy Harvesting

    Science.gov (United States)

    Wiercigroch, M.; Najdecka, A.; Vaziri, V.

    In this paper dynamics of a parametric pendulums system operating in rotational regime has been investigated with a view of energy harvesting. The main idea is based on the conversion of the oscillatory motion of the oscillatory motion into rotation of pendulums [1]. Numerical, analytical and experimental studies have been undertaken on a parametric pendulum and a pendulum excited by a planar motion. They suggest the rotational motion is persisting and occurs for a large range of frequencies and excitation amplitudes, which are the main control parameters. These investigations reinforce the viability of this new concept of the energy conversion. A system of two pendulums has been modelled and analysed. Specifically, the dynamics of the parametric pendulums systems has been investigated numerically and experimentally focusing on synchronized rotational solutions. The target state is a synchronized counter rotation of both pendulums. A control strategy aiming to initiate and maintain the desired rotational responses, has been developed and verified numerically and experimentally.

  19. Optimal satisfaction degree in energy harvesting cognitive radio networks

    Science.gov (United States)

    Li, Zan; Liu, Bo-Yang; Si, Jiang-Bo; Zhou, Fu-Hui

    2015-12-01

    A cognitive radio (CR) network with energy harvesting (EH) is considered to improve both spectrum efficiency and energy efficiency. A hidden Markov model (HMM) is used to characterize the imperfect spectrum sensing process. In order to maximize the whole satisfaction degree (WSD) of the cognitive radio network, a tradeoff between the average throughput of the secondary user (SU) and the interference to the primary user (PU) is analyzed. We formulate the satisfaction degree optimization problem as a mixed integer nonlinear programming (MINLP) problem. The satisfaction degree optimization problem is solved by using differential evolution (DE) algorithm. The proposed optimization problem allows the network to adaptively achieve the optimal solution based on its required quality of service (Qos). Numerical results are given to verify our analysis. Project supported by the National Natural Science Foundation of China (Grant No. 61301179), the Doctorial Programs Foundation of the Ministry of Education of China (Grant No. 20110203110011), and the 111 Project (Grant No. B08038).

  20. 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.

  1. The effect of non-uniform damping on flutter in axial flow and energy harvesting strategies

    OpenAIRE

    Singh, Kiran; Michelin, Sebastien; de Langre, Emmanuel

    2012-01-01

    The problem of energy harvesting from flutter instabilities in flexible slender structures in axial flows is considered. In a recent study, we used a reduced order theoretical model of such a system to demonstrate the feasibility for harvesting energy from these structures. Following this preliminary study, we now consider a continuous fluid-structure system. Energy harvesting is modelled as strain-based damping and the slender structure under investigation lies in a moderate fluid loading ra...

  2. Analysis of a flapping foil system for energy harvesting at low Reynolds number

    OpenAIRE

    Cho, Hunkee

    2011-01-01

    The new type of power generation system which mimics the flapping motion of insects or fish has been studied in recent years. The biological flapping foil is capable of harvesting energy from incoming wind or current. A non- sinusoidal trajectory profile and linear shear inlet profile are proposed for the flapping foil in the energy harvesters instead of conventional sinusoidal plunging and pitching motions to get better energy harvesting performance. In this study we create a numerical model...

  3. Integration of Energy Harvester for Self-Powered Wireless Sensor Network Nodes

    OpenAIRE

    Lijuan Chen; Xiaohui Xu; Pingliang Zeng; Jianqiang Ma

    2014-01-01

    This paper reports an energy harvester suitable for self-powered wireless sensor network (WSN) nodes consisting of a piezoelectric cantilever, an energy harvesting circuit, and a storage capacitor. Having the same size as a credit card, the proposed WSN nodes can be easily integrated into various applications, such as motor and air conditioning equipment. The WSN node is powered by an integrated bimorph piezoelectric generator that harvests energy from ambient vibration. The paper has develop...

  4. Three-dimensional magnetic energy harvester applied for locomotive devices

    Science.gov (United States)

    Tsai, N.-C.; Hsu, S.-L.

    2012-01-01

    An innovative tri-axes micro-power receiver is proposed and studied for wireless magnetic energy transmission. The tri-axes micro-power receiver mainly consists of two sets of 3D micro-solenoids and one set of planar micro-coils in which individually iron core is all embedded. The three sets of micro-coils/micro-solenoids are designed to be orthogonal to each other. Therefore, no matter which direction the input magnetic flux is present along, the supplied magnetic energy can be harvested and transformed into electric power by the proposed micro-power receiver in wireless sense. Not only dead zone of receiving power is greatly reduced, but also transformation efficiency of magnetic energy into electric power can be much enhanced. By Biot-Savart law and Faraday's law, the mathematical description upon power transmission from transmitter to receiver is developed. By employing commercial software, Ansoft Maxwell, based on finite element method, the estimation error on power transmission by mathematical description is revealed. Besides, the preliminary simulation results by Ansoft Maxwell show that the proposed micro-power receiver can efficiently harvest the energy supplied by magnetic power source. The design parameters of tri-axes micro-receiver are hence examined and verified for follow-up fabrication. At last, for the MEMS process, the isotropic etching technique is employed to micro-machine the inverse-trapezoid fillister so that the copper wire can be successfully electroplated. The adhesion between micro-coils and fillister is hence much enhanced as well.

  5. 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. .

  6. 3D, wideband vibro-impacting-based piezoelectric energy harvester

    Science.gov (United States)

    Yu, Qiangmo; Yang, Jin; Yue, Xihai; Yang, Aichao; Zhao, Jiangxin; Zhao, Nian; Wen, Yumei; Li, Ping

    2015-04-01

    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.

  7. 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.

  8. Stripper harvesting of energy grain; Ribbehoest af energikorn

    Energy Technology Data Exchange (ETDEWEB)

    Madsen, N.P.; Soerensen, K.

    2001-05-01

    A two-year study of the applicability of stripper harvesters for harvesting of energy grain (triticale) has been made. Consisting of a front-mounted wind-rower and a trailed stripper harvester, the stripper harvesting system was easy to operate in standing crops. However, quite severe problems often occurred in cases of severely lodged crops. Like other harvesting machines, wind-rowers require even fields with a minimum occurrence of stones in order to obtain a reliable and constant operation at an acceptable capacity. As a part of the project, the capacity of a newly developed chip transporting system for handling of the stripped fraction was studied. The transport system included a semi-trailer equipped with a suction system for loading and a chain conveyor-suction system for direct unloading into storage silos at the combined heat and power (CHP) stations. The loading capacity was very insufficient, and unloading was nearly impossible, due to frequent interruptions in the flow. For heating stations and other consumer facilities to be able to handle the stripped fraction, it became necessary to produce pellets from the material. The stripped fraction was transported to the pellet factory in open containers. It was no problem for the CHP stations to handle the big baled straw fraction, as CHP stations usually have the needed equipment. Both years the weather conditions were unfavourable. What combustion is concerned, however, improvements in the straw quality could already be seen after 30 mm of rainfall. Great reductions in the contents of potassium, chloride and ash were observed, whether or not stripping had occurred. As the weight of a stripped fraction will mainly depend on the content of seeds, only slight reductions in the contents of potassium, chloride and ash will occur as a result of rainfall. As desired, great reductions in the corrosion of CHP station boilers will be obtained during the leaching of straw. If the crops are left in the field, a

  9. 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.

  10. 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. PMID:27579343

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

    Science.gov (United States)

    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. PMID:27579343

  12. Excitation of energy harvesters using stick-slip motion

    Science.gov (United States)

    Helseth, L. E.

    2014-08-01

    During the past decades a large number of energy harvesting systems with the ability to transform mechanical energy into electrical energy have been proposed, ranging from systems exhibiting pure sinusoidal motion to stochastic systems. However, to date little emphasis has been put on stick-slip motion as a method for excitation of energy harvesting systems. Stick-slip motion can be associated with both microscopic and macroscopic processes and is omnipresent. The motion can be characterized by two stages. In the first stage there is buildup of elastic energy with little associated motion, whereas in the second stage the elastic energy is released into kinetic energy. We study here the spectral signal characteristics of two different electrical generators excited by stick-slip motion: a piezoelectric macro fiber composite and a triboelectric generator. The force and the voltage generated during the motion were monitored, and we found that the signal spectral density of both variables changes with the frequency in a characteristic manner, thus classifying the slip-stick motion as a colored noise excitation scheme. The force spectral density in both systems was found to exhibit a power-law spectrum following an {{f}^{-2}} trend, where f is the frequency. The voltage spectral density was governed by the product of a high-pass filter, the force spectral density, and the intrinsic generator spectral density. Here the piezoelectric generator exhibited a nearly flat voltage spectral density below the cutoff frequency of the high-pass filter and an {{f}^{-2}} spectrum at higher frequencies, thus demonstrating that the piezoelectric coupling coefficient had a nearly flat frequency response. On the other hand, the triboelectric generator had a coupling coefficient with a spectral response that varied in a non-systematic manner, possibly related to the large number of contact sites and relaxation times occurring during operation. The average power delivered by the generators

  13. Harmonic balance analysis of nonlinear tristable energy harvesters for performance enhancement

    Science.gov (United States)

    Zhou, Shengxi; Cao, Junyi; Inman, Daniel J.; Lin, Jing; Li, Dan

    2016-07-01

    Nonlinear energy harvesters are very sensitive to ambient vibrations. If the excitation level is too low, their large-amplitude oscillations for high-energy voltage output cannot be obtained. A nonlinear tristable energy harvester has been previously proposed to achieve more effective broadband energy harvesting for low-level excitations. However, the sensitivity of its dynamic characteristics to the system parameters remains uninvestigated. Therefore, this paper theoretically analyzes the influence of the external load, the external excitation, the internal system parameters and the equilibrium positions on the dynamic responses of nonlinear tristable energy harvesters by using the harmonic balance method. In addition, numerical acceleration excitation thresholds and basins of attraction are provided to investigate the potential for energy harvesting performance enhancement using the suitable equilibrium positions, appropriate initial conditions or external disturbances, due to high-energy interwell oscillations in the multi-solution ranges. More importantly, experimental voltage responses of a given tristable energy harvester versus the external excitation frequency and amplitude verify the existence of experimental multi-solution ranges and the effectiveness of the theoretical analysis. It is also revealed that achieving high-energy interwell oscillations in the multi-solution ranges of tristable energy harvesters will be feasible for improving energy harvesting from low-level ambient excitations.

  14. 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.

  15. 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.

  16. 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 .

  17. 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.

  18. 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...

  19. 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 ...

  20. 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.

  1. 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.

  2. Electromagnetic energy harvesting from a dual-mass pendulum oscillator

    Science.gov (United States)

    Wang, Hongyan; Tang, Jiong

    2016-04-01

    This paper presents the analysis of a type of vibration energy harvester composed of an electromagnetic pendulum oscillator combined to an elastic main structure. In this study, the elastic main structure connected to the base is considered as a single degree-of-freedom (DOF) spring-mass-damper subsystem. The electromagnetic pendulum oscillator is considered as a dual-mass two-frequency subsystem, which is composed of a hollow bar with a tip winded coil and a magnetic mass with a spring located in the hollow bar. As the pendulum swings, the magnetic mass can move along the axial direction of the bar. Thus, the relative motion between the magnet and the coil induces a wire current. A mathematical model of the coupled system is established. The system dynamics a 1:2:1 internal resonance. Parametric analysis is carried out to demonstrate the effect of the excitation acceleration, excitation frequency, load resistance, and frequency tuning parameters on system performance.

  3. Performance Analysis and Modelling of a Radio Frequency Energy Harvesting System

    Directory of Open Access Journals (Sweden)

    CIRSTEA, C.

    2013-02-01

    Full Text Available The development of autonomous battery powered systems which can be deployed in inaccessible locations for sensing applications has determined the development of various energy harvesting systems. Such an energy harvester is the one developed by Powercast which can convert the energy of radio frequency signals into useful power. A model of the harvested power can prove to be a useful tool for simulation purposes as it can provide, to some extent, prior knowledge of available energy resources when optimally deploying sensor networks. To obtain an accurate model of the harvested energy we have developed an experimental setup which has been used to determine the harvested power in two different environments, a hallway and a parking lot. We have developed the experimental setup to determine the amount of power available at the output of the radio frequency harvester which consists of a current measurement system and a data acquisition system. We have also modeled through simulations the harvested power based on the characteristics of the transmitter and receiver antennas and those of the environment. We have compared the results obtained through in field measurement with the ones obtained through simulation and we have shown that within certain margins of error of maximum 2 dBm one can successfully predict the amount of energy the system can harvest. However the RF-DC and Boost converter efficiency are also key factors in the quantity of harvested energy.

  4. 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.

  5. Nonlinear time-varying potential bistable energy harvesting from human motion

    Science.gov (United States)

    Cao, Junyi; Wang, Wei; Zhou, Shengxi; Inman, Daniel J.; Lin, Jing

    2015-10-01

    A theoretical and experimental investigation into nonlinear bistable energy harvesting with time-varying potential energy is presented. The motivation for examining time-varying potentials comes from the desire to harvest energy from human motion. Time-varying potential energy function of bistable oscillator with respect to the swing angle are established to derive the governing electromechanical model for harvesting vibration energy from the swaying motion during human walking or running. Numerical simulations show good agreement with the experimental potential energy function under different swing angles. Various motion speed treadmill tests are performed to demonstrate the advantage of time-varying bistable harvesters over linear and monostable ones in harvesting energy from human motion.

  6. 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.

  7. 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

  8. A comparison of power output from linear and nonlinear kinetic energy harvesters using real vibration data

    Science.gov (United States)

    Beeby, Stephen P.; Wang, Leran; Zhu, Dibin; Weddell, Alex S.; Merrett, Geoff V.; Stark, Bernard; Szarka, Gyorgy; Al-Hashimi, Bashir M.

    2013-07-01

    The design of vibration energy harvesters (VEHs) is highly dependent upon the characteristics of the environmental vibrations present in the intended application. VEHs can be linear resonant systems tuned to particular frequencies or nonlinear systems with either bistable operation or a Duffing-type response. This paper provides detailed vibration data from a range of applications, which has been made freely available for download through the Energy Harvesting Network’s online data repository. In particular, this research shows that simulation is essential in designing and selecting the most suitable vibration energy harvester for particular applications. This is illustrated through C-based simulations of different types of VEHs, using real vibration data from a diesel ferry engine, a combined heat and power pump, a petrol car engine and a helicopter. The analysis shows that a bistable energy harvester only has a higher output power than a linear or Duffing-type nonlinear energy harvester with the same Q-factor when it is subjected to white noise vibration. The analysis also indicates that piezoelectric transduction mechanisms are more suitable for bistable energy harvesters than electromagnetic transduction. Furthermore, the linear energy harvester has a higher output power compared to the Duffing-type nonlinear energy harvester with the same Q factor in most cases. The Duffing-type nonlinear energy harvester can generate more power than the linear energy harvester only when it is excited at vibrations with multiple peaks and the frequencies of these peaks are within its bandwidth. Through these new observations, this paper illustrates the importance of simulation in the design of energy harvesting systems, with particular emphasis on the need to incorporate real vibration data.

  9. Energy Harvesting for the Internet-of-Things: Measurements and Probability Models

    OpenAIRE

    Smart, G.; Atkinson, J; Mitchell, J.; Rodrigues, M; Andreopoulos, I.

    2016-01-01

    The success of future Internet-of-Things (IoT) based application deployments depends on the ability of wireless sensor platforms to sustain uninterrupted operation based on environmental energy harvesting. In this paper, we deploy a multitransducer platform for photovoltaic and piezoelectric energy harvesting and collect raw data about the harvested power in commonly-encountered outdoor and indoor scenarios. We couple the generated power profiles with probability mixture models and make our d...

  10. More energy wood from forestry operations through integrated harvesting and multi-products processing

    International Nuclear Information System (INIS)

    Abundant supplies of forest biomass that could potentially be used for energy wood are not being accessed because of marginal economics, inadequate harvest methods, and restrictive land management practices. Future forestry objectives may impose even more restrictive conditions. Improvements in efficiency and effectiveness of harvest methods, marketing, and bureaucratic processes may, however, render more energy wood while meeting new post-harvest stand conditions. Some improvements have been achieved while others lie on the horizon

  11. Energy harvesting from solar cells under typical illumination conditions in buildings

    OpenAIRE

    Li, Yi; Grabham, Neil J.; Beeby, Steve P; Tudor, John

    2013-01-01

    Energy harvesting powered devices have the potential for widespread use in buildings. The most prevalent ambient energy source available in buildings is light, which is normally harvested using photovoltaic devices. The light to be harvested can be from both natural and artificial sources and a range of different types of solar cells are available to suit differing light sources and intensities, and as such must be selected to suit the type of light to be encountered. For use inside buildings...

  12. A Vibration-Based MEMS Piezoelectric Energy Harvester and Power Conditioning Circuit

    OpenAIRE

    Hua Yu; Jielin Zhou; Licheng Deng; Zhiyu Wen

    2014-01-01

    This paper presents a micro-electro-mechanical system (MEMS) piezoelectric power generator array for vibration energy harvesting. A complete design flow of the vibration-based energy harvester using the finite element method (FEM) is proposed. The modal analysis is selected to calculate the resonant frequency of the harvester, and harmonic analysis is performed to investigate the influence of the geometric parameters on the output voltage. Based on simulation results, a MEMS Pb(Zr,Ti)O3 (PZT)...

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

    OpenAIRE

    Hanif SedighNejad; Tariq Iqbal; John Quaicoe

    2014-01-01

    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 communit...

  14. Harvestable vibrational energy from an avian source: theoretical predictions vs. measured values

    Science.gov (United States)

    Shafer, Michael W.; MacCurdy, Robert; Garcia, Ephrahim; Winkler, David

    2012-04-01

    For many reasons, it would be beneficial to have the capability of powering a wildlife tag over the course of multiple migratory seasons. Such an energy harvesting system would allow for more data collection and eliminate the need to replace depleted batteries. In this work, we investigate energy harvesting on birds and focus on vibrational energy harvesting. We review a method of predicting the amount of power that can be safely harvested from the birds such that the effect on their longterm survivability is not compromised. After showing that the safely harvestable power is significant in comparison to the circuits used in avian tags, we present testing results for the flight accelerations of two species of birds. Using these measured values, we then design harvesters that matched the flight acceleration frequency and are sufficiently low mass to be carried by the birds.

  15. 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.

  16. Magnetic plucking of piezoelectric bimorphs for a wearable energy harvester

    Science.gov (United States)

    Pozzi, Michele

    2016-04-01

    A compact and low-profile energy harvester designed to be worn on the outside of the knee-joint is presented. Frequency up-conversion has been widely adopted in recent times to exploit the high frequency response of piezoelectric transducers within environments where only low frequencies are present. Contactless magnetic plucking is here introduced, in a variable reluctance framework, with the aim of improving the mechanical energy transfer into the transducers, which is sub-optimal with contact plucking. FEA and experiments were used to design an optimal arrangement of ferromagnetic teeth to interact with the magnets fixed to the piezoelectric beams. A prototype was made and extensively tested in a knee-joint simulator controlled with gait data available in the literature. Energy and power produced were measured for walking and running steps. A power management unit was developed using off-the-shelf components, permitting the generation of a stable and regulated supply of 26 mW at 3.3 V during walking. Record levels of rectified (unregulated) electrical power of over 50 and 70 mW per walking and running steps, respectively, were measured.

  17. 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.

  18. 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.

  19. 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.

  20. Design and modelling of an energy harvester for tire pressure monitoring systems

    Directory of Open Access Journals (Sweden)

    Zaouali E.

    2014-01-01

    Full Text Available The main objective of this work is to design a kinetic energy harvester for TPMS applications. The energy harvester presented in this work is a multi-pendulum fixed to a rolling wheel, which exploits nonlinear effects rendered by such a design.

  1. 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.

  2. 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....

  3. 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...

  4. 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...

  5. 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

  6. An electromagnetic energy harvester for powering consumer electronics

    Science.gov (United States)

    Liu, Xiyuan

    This thesis introduces an electromagnetic vibratory energy harvester to power consumer electronics by generating electricity from the strides taken during walking or jogging. The harvester consists of a magnetic pendulum oscillating between two fixed magnets. The pendulum behaves similar to a rotor in a DC generator, while the fixed magnets, which are poled opposite to the pendulum, provide magnetic restoring forces similar to mechanical springs. When attached to a person's arm, the swinging motion subjects the magnetic pendulum to base excitations. Consequently, the pendulum oscillates near a stator which has three poles of wound copper coils. The motion of the pendulum induces a time-varying magnetic field in the flux path which generates electricity in the coils as per Faraday's law. To better understand the response behavior of the device, the thesis presents a nonlinear electromechanical model that describes the interaction between the mechanical and electrical subsystems. Experimental system identification is then implemented to characterize several unknown design parameters, including the nonlinear magnetic restoring torque, the mechanical damping coefficient, and the electromechanical coupling. The derived nonlinear mathematical model, which mimics the behavior of a damped Duffing oscillator, is then solved analytically using the method of multiple scales and the results are compared to experimental data showing good agreement for the design parameters considered. The performance of the device in charging a small battery while jogging is investigated. The motion of a typical swinging arm in terms of frequency and acceleration is reproduced on an electrodynamic shaker and used to charge a 100 μAh battery yielding an estimated charging time of 12 minutes.

  7. 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. PMID:18334321

  8. Experimental analysis of energy harvesting from self-induced flutter of a composite beam

    Energy Technology Data Exchange (ETDEWEB)

    Zakaria, Mohamed Y., E-mail: zakaria@vt.edu; Al-Haik, Mohammad Y.; Hajj, Muhammad R. [Virginia Tech, Norris Hall, Blacksburg, Virginia 24061 (United States)

    2015-07-13

    Previous attempts to harvest energy from aeroelastic vibrations have been based on attaching a beam to a moving wing or structure. Here, we exploit self-excited oscillations of a fluttering composite beam to harvest energy using piezoelectric transduction. Details of the beam properties and experimental setup are presented. The effects of preset angle of attack, wind speed, and load resistance on the levels of harvested power are determined. The results point to a complex relation between the aerodynamic loading and its impact on the static deflection and amplitudes of the limit cycle oscillations on one hand and the load resistance and level of power harvested on the other hand.

  9. Analysis of energy harvesting from multiple pendulums with and without mechanical coupling

    Science.gov (United States)

    Malaji, P. V.; Ali, S. F.

    2015-11-01

    Multiple energy harvesters in a single device has become important to harvest enough power for sensors. In such situation presence of mistuning may change the performance of the overall system. This paper studies the issue of presence of mistuning in such system and also extend the study to performance evaluation when mechanically coupling is present between the multiple harvesters. A simple case of two pendulums in a same frame is analysed for electromagnetic energy harvesting. Experiments are carried out to support the numerical evaluation. The study limits its observations to low frequency and low amplitude motions. The observation made are very interesting and intricate.

  10. Comparison of electromagnetic and piezoelectric vibration energy harvesters with different interface circuits

    Science.gov (United States)

    Wang, Xu; Liang, Xingyu; Hao, Zhiyong; Du, Haiping; Zhang, Nong; Qian, Ma

    2016-05-01

    A frequency response analysis has been conducted for a single degree of freedom vibration energy harvester connected to four different interface circuits. The performance and characteristics of both electromagnetic and piezoelectric harvesters have been analysed and compared. The main research outcome is the disclosure of similarity and duality of the electromagnetic and piezoelectric harvesters with different interface circuits. The contribution of this paper is to provide a new method to identify a vibration energy harvester with the best interface circuit and the most stable performance.

  11. A performance-enhanced energy harvester for low frequency vibration utilizing a corrugated cantilevered beam

    Science.gov (United States)

    Kim, In-Ho; Jin, SeungSeop; Jang, Seon-Jun; Jung, Hyung-Jo

    2014-03-01

    This note proposes a performance-enhanced piezoelectric energy harvester by replacing a conventional flat cantilevered beam with a corrugated beam. It consists of a proof mass and a sinusoidally or trapezoidally corrugated cantilevered beam covered by a polyvinylidene fluoride (PVDF) film. Compared to the conventional energy harvester of the same size, it has a more flexible bending stiffness and a larger bonding area of the PVDF layer, so higher output voltage from the device can be expected. In order to investigate the characteristics of the proposed energy harvester, analytical developments and numerical simulations on its natural frequency and tip displacement are carried out. Shaking table tests are also conducted to verify the performance of the proposed device. It is clearly shown from the tests that the proposed energy harvester not only has a lower natural frequency than an equivalent sized standard energy harvester, but also generates much higher output voltage than the standard one.

  12. A dimensionless analysis of a 2DOF piezoelectric vibration energy harvester

    Science.gov (United States)

    Xiao, Han; Wang, Xu; John, Sabu

    2015-06-01

    In this study, a dimensionless analysis method is proposed to predict the output voltage and harvested power for a 2DOF vibration energy harvesting system. This method allows us to compare the harvesting power and efficiency of the 2DOF vibration energy harvesting system and to evaluate the harvesting system performance regardless the sizes or scales. The analysis method is a hybrid of time domain simulation and frequency response analysis approaches, which would be a useful tool for parametric study, design and optimisation of a 2DOF piezoelectric vibration energy harvester. In a case study, a quarter car suspension model with a piezoelectric material insert is chosen to be studied. The 2DOF vibration energy harvesting system could potentially be applied in a vehicle to convert waste or harmful ambient vibration energy into electrical energy for charging the battery. Especially for its application in a hybrid vehicle or an electrical vehicle, the 2DOF vibration energy harvesting system could improve charge mileage, comfort and reliability.

  13. Kinetic and thermal energy harvesters for implantable medical devices and biomedical autonomous sensors

    International Nuclear Information System (INIS)

    Implantable medical devices usually require a battery to operate and this can represent a severe restriction. In most cases, the implantable medical devices must be surgically replaced because of the dead batteries; therefore, the longevity of the whole implantable medical device is determined by the battery lifespan. For this reason, researchers have been studying energy harvesting techniques from the human body in order to obtain batteryless implantable medical devices. The human body is a rich source of energy and this energy can be harvested from body heat, breathing, arm motion, leg motion or the motion of other body parts produced during walking or any other activity. In particular, the main human-body energy sources are kinetic energy and thermal energy. This paper reviews the state-of-art in kinetic and thermoelectric energy harvesters for powering implantable medical devices. Kinetic energy harvesters are based on electromagnetic, electrostatic and piezoelectric conversion. The different energy harvesters are analyzed highlighting their sizes, energy or power they produce and their relative applications. As they must be implanted, energy harvesting devices must be limited in size, typically about 1 cm3. The available energy depends on human-body positions; therefore, some positions are more advantageous than others. For example, favorable positions for piezoelectric harvesters are hip, knee and ankle where forces are significant. The energy harvesters here reported produce a power between 6 nW and 7.2 mW; these values are comparable with the supply requirements of the most common implantable medical devices; this demonstrates that energy harvesting techniques is a valid solution to design batteryless implantable medical devices. (topical review)

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.)

  19. 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.

  20. 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.