Procedure for site discovery, system design, and optimization of power harvesting systems is developed with an emphasis on application to air compressors. Limitations for the usage of infrared pyrometers is evaluated. A system of governing equations for thermoelectric generators is developed. A solution method for solving the system of equations is created in order to predict power output from the device. Payback analysis is proposed for determining economic viability. A genetic algorithm is used to optimize the power harvesting system payback with changing quantities and varieties of thermoelectric generators, as well as the back work put into cooling the thermoelectric generators.Experimental data is taken for laboratory simulation of a power harvesting system under varying resistive load and thermal conductances in order to confirm the working model. A power harvester is designed for and installed on a consumer grade portable air compressor. Experimental data is compared against the model's prediction. As a case study, a system is designed for a water-cooled power harvesting system.Thermoelectric generator power harvesters are found to be economically infeasible for typical installations at current energy prices. Changes in parameters which would increase economic feasibility of the power harvesting system are discussed.

Made available in DSpace on 2014-06-11T19:22:31Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-08-05Bitstream added on 2014-06-13T20:09:42Z : No. of bitstreams: 1 souza_fs_me_ilha.pdf: 685362 bytes, checksum: 69b1ef9da6ea6cde4e9978452b127ff7 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Este trabalho descreve um sistema de extração de potência de power harvesting utilizando transdutores piezelétricos. Com o objetivo de extrair a máxima potência e assim ter um maior rendimento do sistema, foram projetados e testados alguns circuitos eletrônicos. Um circuito de controle com componentes discretos e de baixo consumo foi projetado para controle da chave do retificador chaveado e bias-flip. A energia extraída será utilizada para alimentar um sistema de aquisição de dados e um sensor de temperatura associado a este sistema. O sistema de power harvesting é constituído por uma estrutura mecânica, transdutor piezelétrico, circuito retificador e um conversor CC-CC. Na estrutura mecânica está localizado o transdutor piezelétrico e este transdutor proporciona a conversão de energia mecânica em energia elétrica. Para efeito deste estudo considera-se que o transdutor piezelétrico comporta-se como uma fonte de tensão alternada, que será retificada e armazenada em um supercapacitor, para depois ser utilizada na alimentação do sistema de aquisição de dados. Os conversores CC-CC são utilizados para maximizar a quantidade de energia obtida do transdutor piezelétrico e fornecer tensão ao supercapacitor. No entanto, uma das limitações desses sistemas é a baixa quantidade de energia gerada por esses dispositivos. Assim, para que haja uma minimização das perdas dos circuitos eletrônicos e possa se extrair a máxima potência possível do piezelétrico obtendo um melhor rendimento do sistema, este trabalho investigará a utilização dos circuitos retificadores em ponte, retificador em ponte chaveado, retificador bias-flip e o conversor buck-boost, além de utilizar a energia armazenada para alimentar um sistema de aquisição de dados associados a um sensor de temperatura... / This work describes several circuits for power extracting of power harvesting systems using piezoelectric transducers. In order to extract the maximum power and to achieve the maximum performance of these systems some electronic circuits were projected and tested. A control circuit with discrete components and low power consumption is designed to control switch of the switch-only and bias-flip rectifier. The goal is that the energy extracted is used to supply power electronic devices. That will be, in this work, a temperature sensor that is placed in a difficult access area. The power harvesting system is composed by a mechanical structure, a piezoelectric transducers, a rectifier and a DC-DC converter. The piezoelectric transducers were placed in the mechanical structure, these transducers are responsible to convert mechanical energy into electrical energy. In this work the piezoelectric transducer was considered an AC voltage source. This voltage will be rectified and then stored in supercapacitor, to be used in electronic circuits. The DC-DC converters were used to achieve maximum power from piezoelectric transducer and to supply voltage to the supercapacitor. However, one of the limitations of these systems is the low amount of power generated by the transducer. This way, it is mandatory to reduce the losses at the electronic components and extract the maximum power possible from the piezoelectric to improve the performance. This work investigates the full-bridge rectifier, switch-only rectifier, bias-flip rectifier and buck- boost converter, besides it aims to use the stored energy to supply a temperature sensor. Using the flip-bias rectifier improves the power up to 200%, and the switch-only rectifier by 150% in relation to full-bridge rectifier. And the efficiency changed from 35% (full-bridge)... (Complete abstract click electronic access below)

Various nondestructive testing (NDT) technologies for construction and performance monitoring have been studied for decades. Recently, the rapid evolution of wireless sensor network (WSN) technologies has enabled the development of sensors that can be embedded in concrete to monitor the structural health of infrastructure. Such sensors can be buried inside concrete and they can collect and report valuable volumetric data related to the health of a structure during and/or after construction. Wireless embedded sensors monitoring system is also a promising solution for decreasing the high installation and maintenance cost of the conventional wire based monitoring systems. Wireless monitoring sensors need to operate for long time. However, sensor batteries have finite life-time. Therefore, in order to enable long operational life of wireless sensors, novel wireless powering methods, which can charge the sensors’ rechargeable batteries wirelessly, need to be developed. The optimization of RF wireless powering of sensors embedded in concrete is studied here. First, our analytical results focus on calculating the transmission loss and propagation loss of electromagnetic waves penetrating into plain concrete at different humidity conditions for various frequencies. This analysis specifically leads to the identification of an optimum frequency range within 20-80 MHz that is validated through full-wave electromagnetic simulations. Second, the effects of various reinforced bar configurations on the efficiency of wireless powering are investigated. Specifically, effects of the following factors are studied: rebar types, rebar period, rebar radius, depth inside concrete, and offset placement. This analysis leads to the identification of the 902-928 MHz ISM band as the optimum power transmission frequency range for sensors embedded in reinforced concrete, since antennas working in this band are less sensitive to the effects of varying humidity as well as rebar configurations. Finally, optimized rectennas are designed for receiving and/or harvesting power in order to charge the rechargeable batteries of the embedded sensors. Such optimized wireless powering systems exhibit significantly larger efficiencies than the efficiencies of conventional RF wireless powering systems for sensors embedded in plain or reinforced concrete.

McMaster University in conjunction with an industrial partner has been designing wireless vibrational condition monitoring sensors for implementation on a vibrating screening machine used in mining applications. A limitation with the current sensor design is their dependency on battery power. In order for the sensors to provide real-time continuous streaming of acceleration data, an alternate power supply was required outside of traditional sources such as batteries or wired power. This thesis outlines the research and development of a power system that harvests the kinetic vibrational energy of a mining screen and converts it into electrical energy for use by a wireless sensor node. During development, multiple prototypes were built and evaluated under laboratory conditions. The core concept of the system is an eccentric pendulum mass excited by the external vibrations of the screening machine used to drive a stepper motor generator. The major design obstacle of the project was how to get the system to self initiate. Both a mechanical and an electrical solution were developed to solve this concern. The final prototype design is fully autonomous, able to react to the start up or shut-down of a screening machine, while also providing a continuous power supply to a wireless vibrational analysis sensor as tested in the lab. With minor optimization, this prototype can be turned into a commercial product for industrial implementation and sale. / Thesis / Master of Applied Science (MASc)

No description available.

Submitted by FABRICIO MARQUI SANCHES null (fabriciosmf@yahoo.com.br) on 2016-01-05T12:05:05Z No. of bitstreams: 1 DISSERTAÇÃO-Fabricio_Marqui_Sanches.pdf: 2162339 bytes, checksum: 257059fa1be635fc6245b0168ddbebc4 (MD5) / Approved for entry into archive by Juliano Benedito Ferreira (julianoferreira@reitoria.unesp.br) on 2016-01-06T17:34:12Z (GMT) No. of bitstreams: 1 sanches_fm_me_ilha.pdf: 2162339 bytes, checksum: 257059fa1be635fc6245b0168ddbebc4 (MD5) / Made available in DSpace on 2016-01-06T17:34:13Z (GMT). No. of bitstreams: 1 sanches_fm_me_ilha.pdf: 2162339 bytes, checksum: 257059fa1be635fc6245b0168ddbebc4 (MD5) Previous issue date: 2015-12-11 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Neste trabalho é investigada a viabilidade energética do emprego de buzzers piezelétricos, circuito retificador de onda completa e conversor DC-DC elevador em um sistemas de power harvesting submetido a esforços mecânicos causados pelo tráfego de veículos e/ou caminhar de pedestres, demonstrando a possibilidade de reutilização dessa energia no carregamento de baterias para alimentação de circuitos autônomos de monitoramento, indicação, iluminação, etc., em locais remotos, eliminando ou estendendo os intervalos necessário entre as recargas desses dispositivos. O gerador piezelétrico é analisado mediante a excitação realizada por um cilindro pneumático simulador de impactos controlado eletronicamente com frequência de 0,5 Hz e 1 Hz, contendo diferentes quantidades de PZTs (2, 4 e 8) e configuração de ligação (série ou paralelo). Os resultados extraídos são referentes à tensão elétrica, corrente, potência e energia armazenada em função do tempo, sendo ainda feitas relações dessas grandezas com diferentes números de PZTs, área que ocupam, força e pressão aplicada sobre os mesmos. Ao final pode-se concluir a viabilidade da utilização de dispositivos simples em sistemas de power harvesting para geração de energia através de excitações na forma pulsada e em baixas frequências, sendo os maiores valores na saída do circuito em termos de potência e corrente para tensão de 5 volts, 108 µW e 21,5 µA (0,53 Kg e 0,83 N/cm2), bem como 118,8 µW e 23,6 µA para (2,13 Kg e 3,33 N/cm2), obtidos com 8 PZTs, conectados em paralelo e excitados a 1 Hz. / This paper investigated the energy viability of the use of piezoelectric buzzers, rectifier circuit full-wave and DC-DC-converter in a power harvesting systems subjected to mechanical stress caused by the traffic of vehicles and / or walk for pedestrians, demonstrating the possibility of re-use of energy in charging batteries to power autonomous monitoring circuits, display, illumination, etc., in remote locations, eliminating or extending the intervals needed between charges these devices. The piezoelectric generator is analyzed through excitation carried out by a pneumatic cylinder simulator electronically controlled impacts with a frequency of 0.5 Hz and 1 Hz, containing different amounts of PZTs (2, 4, 8) and connection configuration (parallel or serial) . The extracted results are related to the voltage, current, power and energy stored in function of time, still being made relations of these quantities for the number of PZTs, area they occupy, force and pressure applied on them. At the end we can conclude the feasibility of using simple devices in power harvesting systems to generate energy through excitations in pulsed manner and at low frequencies, with higher values in the circuit output in terms of power and current to voltage 5 volts, 108 µW and 21,5 µA (0,53 Kg and 0,83 N/cm2), just like 118,8 µW and 23,6 µA to (2,13 Kg e 3,33 N/cm2), obtained with 8 PZTs, connected in parallel and excited to 1 Hz.

Submitted by Maria Suzana Diniz (msuzanad@hotmail.com) on 2015-11-05T15:02:58Z No. of bitstreams: 1 arquivototal.pdf: 2263650 bytes, checksum: 4d60464c07f78fb9c03a13252617e730 (MD5) / Made available in DSpace on 2015-11-05T15:02:58Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 2263650 bytes, checksum: 4d60464c07f78fb9c03a13252617e730 (MD5) Previous issue date: 2015-07-24 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / This work to characterize a thermoelectric device as a electrical power generator. For this propose, a thermoelectric cell was submit to different temperature profiles on his faces. The application of heat on the device was made through a feeded back controled structure with cascade Peltier cells, temperature sensors and current circuit drivers. The execution and the monitoring of this was made by an interface of acquisition and data control connected to the computer and managed by a software dedicated to this application. With this experiments was observed the electrical voltage response from the thermoelectric device in relation to temperatures applied to his faces. Also was inserted a resistive charge for behavior analysis of the electrical power provided by the device. Among the obtained results, stand out the variation of the Seebeck coefficient when the average of work’s temperature changes. The power provided by the thermoelectric device setted as generator comes to 95 mW when submitted to a temperature difference ((ΔT) in 40 ºC. The power and current curves are showed in relation to the voltage generated by the device. / Este trabalho caracteriza um dispositivo termoelétrico como gerador de energia elétrica. Para tal propósito, uma célula termoelétrica foi submetida a diferentes perfis de temperatura em suas faces.A aplicação de calor no dispositivo foi feita através de uma estrutura de controle retroalimentada composta por células de Peltier em cascata,sensores de temperatura e circuitos condicionadores de corrente. A execução e o monitoramento do sistema foram feitos através de uma interface de aquisição e controle de dados, conectada a um computador e gerenciada por um software dedicado a aplicação. Com estes experimentos foi observada a resposta da tensão elétrica do dispositivo termoelétrico em relação às temperaturas aplicadas em suas faces. Também foi inserida uma carga resistiva para analise do comportamento da potência elétrica fornecida pelo dispositivo. Dentre os resultados obtidos, destaca-se a variação do coeficiente de Seebeck quando é variada a temperatura média de trabalho. A potência fornecida pelo dispositivo termoelétrico configurado como gerador chega a 95 mW quando submetido a uma diferença de temperatura (ΔT) de 40 ºC.A curva de potência e corrente elétrica são apresentadas em relação à tensão gerada pelo dispositivo.

Piezoelectric power harvesting is a field of active research. Most piezoelectric power harvesters are designed around harvesting energy from vibrations. This thesis is a feasibility study in collaboration with SKF to investigate whether or not a useful amount of power can be extracted from a piezoelectric tube mounted inside the roller of a bearing, based purely on harvesting power from mechanical strain instead of ambient vibrations, with the goal of replacing bulky single-use batteries as the power source for SKF's sensor roller technology. The methodology consisted of constructing and simulating a multiphysics model in COMSOL Multiphysics, and simulations were performed using three sets of parametric studies. Necessary material properties for the middle epoxy layer bonding the roller and piezo tube together were determined, before characterizing the piezoelectric behavior in relation to the magnitude of the applied load and the rotation of the roller. Simulation results indicate that approximately 0.64mW of power can be harvested from a single piezo tube under nominal operation in the test case, which is sufficient to power the sensor roller circuitry. In addition to simply replacing batteries as a power source, the technology opens up possibilites for more widespread adoption of sensor rollers in other applications.

Made available in DSpace on 2015-05-08T14:57:18Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 2859184 bytes, checksum: 1715e0300f8f547f3f4d0e5ea3c865ab (MD5) Previous issue date: 2014-02-28 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / This work presents a characterization study of a piezoelectric element for generating electricity. This characterization allowed the determination of the relationship between mechanical deformation experienced by the element generator (piezoelectric) and the electric power generated. The results of the study were based on simulations using a finite element program (ANSYS) and experimental data. Was used the ceramic Lead Zirconate Titanate (PZT) as the piezoelectric element of the generator. We developed a generator comprised of a basic cantilever beam excited by a shaker (exciter) at the frequencies of interest. With the use of this generator, it was established that the maximum voltage generation and electrical power occurred at a frequency of 75 Hz. For a load of 19.69 kΩ, which divided the voltage generated under no load condition by half at the frequency of 75 Hz, it was provided an electric power of 1,877 mW for a deformation of 387,97 μm/m on the PZT. For this frequency, the results of elastic deformation and voltage in the simulations, showed to be equivalent to those achieved in the experiment. / Este trabalho apresenta um estudo de caracterização de um elemento piezoelétrico para geração de energia elétrica. Essa caracterização permitiu a determinação da relação entre a deformação mecânica sofrida pelo elemento gerador (piezoelétrico) e a potência elétrica gerada. Os resultados obtidos pelo estudo foram baseados em simulações utilizando um programa de elementos finitos (Ansys) e em dados experimentais. Como elemento piezoelétrico gerador foi utilizada a cerâmica piezoelétrica de Zirconato Titanato de Chumbo (PZT). Para a obtenção dos resultados experimentais, foi desenvolvido um gerador composto por uma viga monoengastada excitada por um shaker (excitador) nas frequências de interesse. Com a utilização deste gerador foi possível constatar que a máxima geração de tensão e potência elétrica ocorreu na frequência de 75 Hz. Para uma carga de 19,69 kΩ, que dividiu, a tensão elétrica gerada em circuito aberto, pela metade na frequência de 75 Hz, foi fornecida uma potência elétrica de 1,877 mW para uma deformação de 387,97 μm/m sobre o PZT. Para esta frequência, os resultados obtidos de deformação elástica e tensão elétrica nas simulações, se mostraram equivalentes aos alcançados no experimento.

Master’s Thesis deals with obtaining electricity from the vibrations of the surrounding environment through piezoelectric vibration generator. To simulation piezoceramics and design mechanical parts of the generator was used simulation program ANSYS 10.0. First, parameters of the designed piezoelectric generator were numerically calculated, and then these values were compared with the real sample. Further work is in the description of material properties of piezo materials.