PZT and Electrode Enhancements of Mems Based Micro Heat Engine for Power Generation

2002 ◽  
Vol 730 ◽  
Author(s):  
A.L. Olson ◽  
L.M. Eakins ◽  
B.W. Olson ◽  
D.F. Bahr ◽  
C.D. Richards ◽  
...  
Keyword(s):  
Bottom Electrode ◽  
Mechanical Energy ◽  
Electrical Power ◽  
Heat Engine ◽  
Mems Devices ◽  
Stress Concentrations ◽  
Process Yield ◽  
Micro Heat Engine ◽  
Reducing Stress ◽  
And Diffusion

AbstractThe P3 Micro Heat Engine relies on a thin film PZT based transducer to convert mechanical energy into usable electrical power. In an effort to increase process yield for these were used on sputtered Ti/Pt bottom electrodes to compare roughness, grain size, and diffusion for annealing temperatures between 550 and 700 °C. For an optimized bottom electrode, process yield for various sized top electrodes were then studied for PZT thickness between 0.54 and 1.62 for reducing stress concentrations. Two PZT etching geometries on 2.3 μm thick Si/SiO2 membranes, with 1.5-3.5 mm side-lengths, were examined and one was used to increase the strain at failure by at least 40%. Integrating improvements in process yield and strain at failure, single PZT based MEMS devices capable of generating power of up to 1 mW and in excess of 2 volts have been demonstrated operating at frequencies between 300 and 1,100 Hz.

Low Frequency Operation of the P3 Micro Heat Engine

2002 ◽  
Author(s):  
Scott A. Whalen ◽  
Michael R. Thompson ◽  
Cecilia D. Richards ◽  
David F. Bahr ◽  
Robert F. Richards
Keyword(s):  
Combustion Engine ◽  
Thermal Power ◽  
Electrical Power ◽  
Heat Engine ◽  
Low Frequency ◽  
Thermodynamic Cycle ◽  
Mechanical Power ◽  
Peak Voltage ◽  
Macro Scale ◽  
Micro Heat Engine

The development and low frequency testing of a micro heat engine is presented. Production of electrical power by a dynamic micro heat engine is demonstrated. The prototype micro heat engine is an external combustion engine in which thermal power is converted to mechanical power through a novel thermodynamic cycle. Mechanical power is converted into electrical power through the use of a thin-film piezoelectric membrane generator. This design is well suited to photolithography-based batch fabrication methods and is unlike any conventionally manufactured macro-scale engine. A peak-to-peak voltage of .84 volts, and power output of 1.5 microwatts have been realized at operating speeds of 10 Hz. Measurements are also presented for the engine operating at resonant conditions. Cycle speeds up to 240 Hz have been obtained, with peak-to-peak voltages of 70 millivolts.

Characterization of the Thermodynamic Working Cycle in a MEMS-Based Micro Heat Engine

2003 ◽  
Author(s):  
S. A. Whalen ◽  
L. W. Weiss ◽  
C. D. Richards ◽  
D. F. Bahr ◽  
R. F. Richards
Keyword(s):  
Mechanical Energy ◽  
Michelson Interferometer ◽  
Heat Engine ◽  
Working Fluid ◽  
Resistance Thermometer ◽  
Working Cycle ◽  
Displacement Profile ◽  
Micro Heat Engine ◽  
Center Deflection

This work examines the conversion of thermal to mechanical energy in a micro heat engine by characterizing the heat engine’s working cycle. Results are given for dynamic measurements of pressure, volume, and temperature throughout the working cycle of the engine. Engine pressure is determined from the deformation of the two membranes in contact with the working fluid. A Michelson interferometer is used to measure the center deflection and displacement profile of both of these membranes. Pressure is determined from the membrane deflection using experimental static pressure-deflection curves. Engine temperature is measured using electrical resistance thermometry, via a micro resistance thermometer fabricated on the surface of a silicon membrane exposed to the working fluid in the engine cavity.

The Mechanical Behavior of a Micromachined PZT Membrane

2003 ◽  
Author(s):  
I. Demir ◽  
R. F. Richards ◽  
D. F. Bahr ◽  
C. D. Richards
Keyword(s):  
Thin Film ◽  
Mechanical Behavior ◽  
Material Properties ◽  
Energy Minimization ◽  
Variational Approach ◽  
Piezoelectric Ceramic ◽  
Electrical Power ◽  
Heat Engine ◽  
Silicon Membrane ◽  
Micro Heat Engine

The mechanical behavior of a micromachined PZT membrane for power applications is investigated. The membrane is a bulk-micromachined silicon membrane that supports a thin film of piezoelectric ceramic (PZT) sandwiched between platinum and gold electrodes. The membrane undergoes large periodic deflections to convert mechanical power to electrical power in a micro heat engine. An analysis using a variational approach is developed to find an approximate closed from solution based on energy minimization. Experiments were conducted to obtain material properties, residual stresses, and pressure deflection relationships. The modeled results compare well to the experimental results.

Miniature Shape Memory Alloy Heat Engine for Powering Wireless Sensor Nodes

2014 ◽  
Vol 1 (1-2) ◽  
Author(s):  
Dragan Avirovik ◽  
Ravi A. Kishore ◽  
Dushan Vuckovic ◽  
Shashank Priya
Keyword(s):  
Shape Memory ◽  
Mechanical Energy ◽  
Electrical Power ◽  
Heat Engine ◽  
Electrical Energy ◽  
Sensor Nodes ◽  
Wireless Sensor ◽  
Wireless Sensor Node ◽  
Wireless Sensor Nodes ◽  
Sensing Platform

AbstractShape Memory Alloys (SMAs) exhibit temperature-dependent cyclic deformation. SMAs undergo reversible phase transformation with heating that generates strain which can be used to develop heat engine. In this study, we build upon the concept where environmental heat is first converted into mechanical energy through SMA deformation and then into electrical energy using a microturbine. This SMA heat engine was tailored to function as a miniature energy harvesting device for wireless sensor nodes applications. The results showed that 0.12 g of SMA wire produced 2.6 mW of mechanical power which was then used to drive a miniature electromagnetic generator that produced 1.7 mW of electrical power. The generated electrical energy was sufficient to power a wireless sensor node. Potential design concepts are discussed for further improvements of the SMA heat engine for the wireless sensing platform.

Design of a Micro Heat Engine

2000 ◽  
Author(s):  
C. Xu ◽  
J. Hall ◽  
C. Richards ◽  
D. Bahr ◽  
R. Richards
Keyword(s):  
Combustion Engine ◽  
Thermal Power ◽  
Electrical Power ◽  
Heat Engine ◽  
Thermodynamic Cycle ◽  
Mechanical Power ◽  
Carnot Cycle ◽  
Mems Fabrication ◽  
Micro Heat Engine ◽  
External Combustion

Abstract The design for a totally new class of heat engine, a micro heat engine, which takes advantage of thermophysical phenomena unique to small scales, is introduced. The proposed engine is an external combustion engine, in which thermal power is converted to mechanical power through the use of a novel thermodynamic cycle which approaches the ideal vapor Carnot cycle. Mechanical power is converted into electrical power through the use of a piezoelectric generator. The generator, which takes the form of a flexible membrane, can be readily manufactured using MEMS fabrication techniques but still delivers high conversion efficiency. This approach eliminates the requirement to manufacture complex micromachines such as rotary compressors and turbines, resulting in a very simple but highly efficient device.

The P3 Micro Power Generation System

2001 ◽  
Author(s):  
C. Richards ◽  
D. Bahr ◽  
C.-G. Xu ◽  
R. Richards
Keyword(s):  
Power Generation ◽  
Combustion Engine ◽  
Thermal Power ◽  
Electrical Power ◽  
Heat Engine ◽  
Mechanical Power ◽  
Carnot Cycle ◽  
Generation System ◽  
Power Generation System ◽  
Micro Heat Engine

Abstract Work toward the development of a new MEMS power generation system, the P3 micro heat engine, is presented. The P3 micro heat engine is an external combustion engine, in which thermal power is converted to mechanical power through the use of a novel thermodynamic cycle that approaches the ideal vapor Carnot cycle. Mechanical power is converted into electrical power through the use of a thin-film piezoelectric membrane generator. A numerical model of the engine, SIMP3, is introduced. The model is used, first to illustrate the micro heat engine’s operation, and then to explore the optimization of the engine. The major parameters controlling the performance of the P3 micro engine are discussed.

A Micro Heat Engine for MEMS Power (Keynote Paper)

2002 ◽  
Author(s):  
C. D. Richards ◽  
D. F. Bahr ◽  
R. F. Richards
Keyword(s):  
Combustion Engine ◽  
Thermal Power ◽  
Electrical Power ◽  
Heat Engine ◽  
Thermodynamic Cycle ◽  
Mechanical Power ◽  
Batch Fabrication ◽  
Macro Scale ◽  
Micro Heat Engine ◽  
External Combustion

Progress in the development of a micro heat engine is presented. The prototype micro heat engine is an external combustion engine, in which thermal power is converted to mechanical power through the use of a novel thermodynamic cycle. Mechanical power is converted into electrical power through the use of a thin-film piezoelectric membrane generator. The design, well suited to photolithography-based batch fabrication methods, is unlike any conventionally manufactured macro-scale engine. In this paper, the design, fabrication and preliminary testing of a working prototype are discussed. The operation of the engine and its key component, the piezoelectric membrane generator is presented. For the first time, the production of electrical power by a dynamic micro heat engine is demonstrated.

scholarly journals Experimental travelling waves identification in mechanical structures

2017 ◽  
Vol 24 (1) ◽  
pp. 152-167
Author(s):  
Izhak Bucher ◽  
Ran Gabai ◽  
Harel Plat ◽  
Amit Dolev ◽  
Eyal Setter
Keyword(s):  
Energy Flux ◽  
Power Flow ◽  
Reactive Power ◽  
Mechanical Energy ◽  
Travelling Waves ◽  
Electrical Power ◽  
Normal Modes ◽  
Standing Waves ◽  
Amplitude Curve ◽  
Physical Point

Vibrations are often represented as a sum of standing waves in space, i.e. normal modes of vibration. While this can be mathematically accurate, the representation as travelling waves can be compact and more appropriate from a physical point of view, in particular when the energy flux along the structure is meaningful. The quantification of travelling waves assists in computing the energy being transferred and propagated along a structure. It can provide local as well as global information about the structure through which the mechanical energy flows. Presented in this paper is a new method to quantify the fraction of mechanical power being transmitted in a vibration cycle at a specific direction in space using measured data. It is shown that the method can detect local defects causing slight non-uniformity of the energy flux. Equivalence is being made with the electrical power factor and electromagnetic standing waves ratio, commonly employed in such cases. Other methods to perform experiment based wave identification in one-dimension are compared with the power flow based identification. Including a signal processing approach that fits an ellipse to the complex amplitude curve and Hilbert transform for obtaining the local phase and amplitude. A new representation of the active and reactive power flow is developed and its relationship to standing waves ratio is demonstrated analytically and experimentally.

THERMAL CONTROL OF MECHANOCHEMICAL REACTION

2021 ◽  
pp. 3-10
Author(s):  
Yu. Tolchinsky ◽  
V. Ved ◽  
I. Rofe-Beketova
Keyword(s):  
Heat Exchange ◽  
Block Diagram ◽  
Mechanical Energy ◽  
Thermal Control ◽  
Solid Particles ◽  
Mechanochemical Reaction ◽  
Flow Mode ◽  
Stress Concentrations ◽  
Reaction Heat ◽  
Crushed Material

Mechanochemistry studies and explains the processes of chemical and physicochemical transformations that are generated by mechanical action on a substance. When carrying out deep mechanochemical transformations, as a rule, it is necessary to transfer to solid reagents a portion of energy comparable to the energy of interatomic bonds. For this, various machines and apparatus are used, such as extruders, in which mechanical energy is constantly transferred to the crushed material. The article discusses the interaction of two reagents in a simple chemical reaction in the state of a mixture of particles of two types, which occurs during compression of particles having a rough irregular shape, and colliding with each other, forming areas of contact. Significant stress concentrations and heating of the substance with the formation of a new phase arise in these regions. Thermal control of the mechanochemical reaction is to maintain an optimal balance of dissipative heat and heat from the coolant in the worm reactor so that the rate of flow and the final product of the reaction meet the specified specifications. The formulas provided in the article for calculating the coefficient of the rate of mechanochemical reaction, heat transfer between worm reactor and jacket channel, heat exchange between jacket and environment allows to calculate the balance conditions for thermal management. The block diagram of the technological line, which is presented in the article, is more economical in comparison with carrying out the same reaction in a solvent. The economic benefit lies in the elimination of the steps of introducing and removing the solvent from the reaction product. At the end, it is indicated that the mechanochemical reaction of the transformation of a mixture of two dispersed materials consisting of solid particles into a liquid can be realized in continuous conditions in a flow mode in a worm machine. And thermal control of the course of a mechanochemical reaction can be carried out using controlled heat exchange with a coolant in a jacket under conditions of turn-around spatial dispersion.

PZT ceramic particles/polyurethane composites formalism for mechanical energy harvesting

2020 ◽  
Vol 89 (3) ◽  
pp. 30901 ◽  
Author(s):  
Abdelkader Rjafallah ◽  
Abdelowahed Hajjaji ◽  
Fouad Belhora ◽  
Abdessamad El Ballouti ◽  
Samira Touhtouh ◽  
...  
Keyword(s):  
Polymer Composites ◽  
Electromechanical Coupling ◽  
Piezoelectric Coefficient ◽  
Mechanical Energy ◽  
Electrical Power ◽  
Ferroelectric Ceramic ◽  
Ferroelectric Ceramics ◽  
High Compliance ◽  
Polyurethane Composites ◽  
Good Agreement

More recently, the ferroelectric ceramic/polymer composites have been progressively replacing ferroelectric ceramics and polymers as they combine their interesting properties. Such as high compliance of polymers and high electromechanical coupling of ferroelectric ceramics those are required for piezoelectric transducer applications. At the same time, the ferroelectric ceramic/polymer composites formalism for predicting their energy-conversion capabilities is of both academic and industrial interest. The novelty of this paper is that the electrical power harvested by the PZT/PU polarized composite has been expressed in terms of the effective longitudinal piezoelectric coefficient (d33) of the composite via a parameter p related to the poling ratio. Besides, the parameter p, that is characterizing the PZT/PU composites with different longitudinal piezoelectric coefficients (d33), was evaluated. The other parameters of the electrical power expression were calculated using the Yamada model for the dielectric, piezoelectric and elastic constants. Finally, a good agreement was found between experience and model.

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