Development of Scaling Model for a MEMS-Based Micro Heat Engine

2010 ◽  
Author(s):  
H. Bardaweel ◽  
B. S. Preetham ◽  
R. Richards ◽  
C. Richards ◽  
M. Anderson
Keyword(s):  
Combustion Engine ◽  
Heat Engine ◽  
Working Fluid ◽  
Thin Membranes ◽  
Micro Heat Engine ◽  
Heat Of Evaporation ◽  
Major Factors ◽  
Engine Components ◽  
External Combustion ◽  
Thermal Physical Properties

In this work we investigate issues related to scaling of a MEMS-based resonant heat engine. The engine is an external combustion engine made of a cavity encapsulated between two thin membranes. The cavity is filled with saturated liquid-vapor mixture working fluid. We use both model and experiment to investigate scaling of the MEMS-based resonant heat engine. The results suggest that the performance of the engine is determined by three major factors: geometry of the engine, speed of operation, and thermal physical properties of engine components. Larger engine volumes, working fluids with higher latent heat of evaporation, slower engine speeds, and compliant expander structures are shown to be desirable.

scholarly journals OPTIMIZATION OF MECHANICAL STRENGTH OF ROTARY-VANE ENGINE

2017 ◽  
Vol 3 ◽  
pp. 357
Author(s):  
Yury Zhuravlev ◽  
Andrey Perminov ◽  
Yury Lukyanov ◽  
Sergey Tikhonov ◽  
Alexander Ilyin ◽  
...  
Keyword(s):  
Mechanical Strength ◽  
Heat Engine ◽  
Fluid Pressure ◽  
Internal Combustion ◽  
Working Fluid ◽  
Drive Torque ◽  
Cam Mechanism ◽  
Inertial Moment ◽  
Engine Components ◽  
External Combustion

The article discusses a rotory-vane heat engine with a lever-cam mechanism motion conversion (an engine may be an internal combustion or external combustion). The output shaft of the engine adds drive torque from the working fluid pressure forces acting on the blade and the inertial moment of the forces of inertia of engine components. The mechanical strength of the motor is dependent on the magnitude and phase of these two torque. The purpose of the article is to determine the conditions under which mechanical strength is minimized.

A New Heat Engine and its Applications in Concentrating Solar Power (CSP)

2012 ◽  
Author(s):  
Yiding Cao
Keyword(s):  
Heat Source ◽  
Internal Combustion Engines ◽  
Solar Power ◽  
Combustion Engine ◽  
Heat Engine ◽  
Working Fluid ◽  
Concentrating Solar Power ◽  
Time Duration ◽  
Combustion Gas ◽  
External Combustion

This paper introduces a new heat engine using a gas, such as air or nitrogen, as the working fluid that extracts thermal energy from a heat source as the energy input. The heat engine is to mimic the performance of an air-standard Otto cycle. This is achieved by drastically increasing the time duration of heat acquisition from the heat source in conjunction with the timing of the heat acquisition and a large heat transfer surface area. Performance simulations show that the new heat engine can potentially attain a thermal efficiency above 50% and a power output above 100 kW under open-cycle operation. Additionally, it could drastically reduce engine costs and operate in open cycles, effectively removing the difficulties of dry cooling requirement. The new heat engine may find extensive applications in renewable energy industries, such as concentrating solar power and geothermal energy power. Furthermore, the heat engine may be employed to recover energy from exhaust streams of internal combustion engines, gas turbine engines, and various industrial processes. It may also work as a thermal-to-mechanical conversion system in a nuclear power plant, and function as an external combustion engine in which the heat source is the combustion gas from an external combustion chamber.

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.

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.

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.

A Micro Heat Engine Executing an Internal Carnot Cycle

2008 ◽  
Author(s):  
Eli Lurie ◽  
Abraham Kribus
Keyword(s):  
Strong Dependence ◽  
Heat Engine ◽  
Thermodynamic Cycle ◽  
Maximum Power ◽  
Working Fluid ◽  
Carnot Cycle ◽  
Heating And Cooling ◽  
Engine Design ◽  
Power Point ◽  
Micro Heat Engine

A micro heat engine, based on a cavity filled with a stationary working fluid under liquid-vapor saturation conditions and encapsulated by two membranes, is described and analyzed. This engine design is easy to produce using MEMS technologies and is operated with external heating and cooling. The motion of the membranes is controlled such that the internal pressure and temperature are constant during the heat addition and removal processes, and thus the fluid executes a true internal Carnot cycle. A model of this Saturation Phase-change Internal Carnot Engine (SPICE) was developed including thermodynamic, mechanical and heat transfer aspects. The efficiency and maximum power of the engine are derived. The maximum power point is fixed in a three-parameter space, and operation at this point leads to maximum power density that scales with the inverse square of the engine dimension. Inclusion of the finite heat capacity of the engine wall leads to a strong dependence of performance on engine frequency, and the existence of an optimal frequency. Effects of transient reverse heat flow, and ‘parasitic heat’ that does not participate in the thermodynamic cycle are observed.

scholarly journals Analysis of a second order thermodynamic model for the performance analysis of a Stirling engine prototype

2018 ◽  
Author(s):  
Miguel Torres García ◽  
Elisa Carvajal Trujillo ◽  
José Antonio Vélez Godiño ◽  
David Sánchez Martínez
Keyword(s):  
High Efficiency ◽  
Combustion Engine ◽  
Numerical Models ◽  
Operational Reliability ◽  
Stirling Engine ◽  
Working Fluid ◽  
Simple Type ◽  
Engine Model ◽  
External Combustion ◽  
External Combustion Engine

The Stirling engine is a simple type of external-combustion engine with an external combustion engine based on cyclic compression and expansion of gas at different temperature levels. It has high efficiency; low vibration levels, simple structure and can run on any combustible fuels. It has been the object of numerous studies. This paper presents an analysis of a Stirling engine model GENOA 03 for electric power generation, of 3 KW of nominal power with pressurized air as working fluid, currently under development. To improve its performance and ensure a good operational reliability, it is necessary to carry out a modelling of the engine in all its operating range. This requires complex numerical models that simulate the behaviour of any element of the engine in a cycle. Two typologies of thermodynamic models are developed in this work: isothermal and adiabatic. The main benefits and shortcomings of each model are mentioned. The geometry and conditions of the engine have been adapted through the Matlab ® tool, in order to obtain the operative conditions of the cooler that you want to replace, as well as an approximation to the expected behaviour.

A MEMS-Based Micro Heat Engine With Integrated Thermal Switch

2006 ◽  
Author(s):  
L. W. Weiss ◽  
J. H. Cho ◽  
D. J. Morris ◽  
D. F. Bahr ◽  
C. D. Richards ◽  
...  
Keyword(s):  
Silicon Nitride ◽  
Heat Engine ◽  
Working Fluid ◽  
Operating Pressure ◽  
Work Output ◽  
Silicon Membrane ◽  
Thermal Switch ◽  
Silicon Nitride Membrane ◽  
Micro Heat Engine ◽  
Membrane Deflection

This work details the effect of top membrane compliance on the performance of a MEMS based micro-heat engine and integrated thermal switch at operating speeds of 20, 40, and 100Hz and heat inputs of up to 60mJ per cycle. The engine consists of two flexible membranes encapsulating a volume of saturated working fluid. A thermal switch is used to intermittently reject heat from the engine to a constant temperature cooling sink. Mechanical work output is measured based on the engine's top membrane deflection and internal operating pressure. Three top membranes are considered; a 2micron thick silicon membrane, a 300nm thick silicon-nitride membrane, and a 3micron thick corrugated silicon membrane. The engine is shown to produce 1.0mW of mechanical power when operated at 100Hz.

Demonstration of an external combustion micro-heat engine

2009 ◽  
Vol 32 (2) ◽  
pp. 3099-3105 ◽  
Author(s):  
Jeong-Hyun Cho ◽  
Chien Shung Lin ◽  
Cecilia D. Richards ◽  
Robert F. Richards ◽  
Jeongmin Ahn ◽  
...  
Keyword(s):  
Heat Engine ◽  
Micro Heat Engine ◽  
External Combustion
Sign in / Sign up

Export Citation Format

Share Document