Design and Optimization of Free Piston Expander for Energy Harvesting

2013 ◽  
Author(s):  
C. Champagne ◽  
L. Weiss
Keyword(s):  
Low Temperature ◽  
Waste Heat ◽  
Operating Efficiency ◽  
Small Scale ◽  
Operational Parameters ◽  
Piston Motion ◽  
Cross Sectional ◽  
Free Piston ◽  
Power Sources ◽  
Potential System

There is a growing opportunity and need for research that investigates alternate power sources. One such source is low temperature waste heat, or energy cast off to the environment as part of some larger process. Through the capture and use of this abundant energy source for power production, it is possible to enhance the overall operating efficiency of the larger system. This presents significant potential for sustainability increase and energy savings. One potential system that can operate from these sources is a low temperature, small-scale steam expander. Investigations of one such device called a Free Piston Expander (FPE) are presented in this work. In final form, the FPE will be a MEMS based device capable of operation as part of a complete low temperature steam system. In this present study, a millimeter scale device is constructed and tested to yield insight into critical operational parameters for future microfabricated designs. Construction of this testbed device is via concentric copper tubing, allowing an effective baseline study of these determining parameters. Parameters studied include device cross sectional area and shape as well as operational pressure. Once consistent parameters are determined, three separate variations of circular FPE design are further tested. These FPEs are designed to either constrain piston rotation or allow for rotational freedom during operation. Testing is performed on these devices for consistency in piston motion. Piston motion is characterized based on a single expansion and reaction of the piston.

Investigation of a MEMS-Based Boiler and Free Piston Expander for Energy Harvesting

2012 ◽  
Author(s):  
C. Champagne ◽  
L. Weiss
Keyword(s):  
Dynamic Testing ◽  
Waste Heat ◽  
Maximum Velocity ◽  
Operating Conditions ◽  
Small Scale ◽  
Operational Parameters ◽  
Piston Motion ◽  
Free Piston ◽  
Static Test ◽  
And Performance

Initial investigations of a small-scale Free Piston Expander (FPE) are presented. In final form, the FPE will be a MEMS-based device capable of operation from low temperature waste heat sources. In this present study, a millimeter scale device is constructed and tested to yield insight into critical operational parameters. Different constructions and operating conditions are considered as are the effects on basic piston motion and performance. These include piston length and mass. In addition, different sealing and lubricating fluids are considered. Construction of this testbed device is via concentric copper tubing, allowing an effective baseline study of these determining parameters. Results show that, while thick lubricants seal well in a static test, piston motion is decreased in a dynamic test indicating leakages. By contrast, reduced viscosity lubricants dont seal as well in a static test, but yield increased piston motion in dynamic testing. This indicates effective sealing. The trends established by the study of varying viscosity lubricants hold true for pistons of increasing mass and length as well. A mixture of isopropanol and water performed well in these tests, and represented a low viscosity sealing fluid. Compared to conditions where no lubricant was used, maximum velocity was increased up to 50%. These results indicate that a thin, wetting fluid will be the best lubricant for the FPE, due to increased sealing and performance when in dynamic operation.

scholarly journals 2D Nanomaterials for Effective Energy Scavenging

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Md Al Mahadi Hasan ◽  
Yuanhao Wang ◽  
Chris R. Bowen ◽  
Ya Yang
Keyword(s):  
Large Scale ◽  
Waste Heat ◽  
Material Selection ◽  
Power Supplies ◽  
Small Scale ◽  
Energy Scavenging ◽  
Power Sources ◽  
Practical Applications ◽  
2D Nanomaterials ◽  
Self Powered

AbstractThe development of a nation is deeply related to its energy consumption. 2D nanomaterials have become a spotlight for energy harvesting applications from the small-scale of low-power electronics to a large-scale for industry-level applications, such as self-powered sensor devices, environmental monitoring, and large-scale power generation. Scientists from around the world are working to utilize their engrossing properties to overcome the challenges in material selection and fabrication technologies for compact energy scavenging devices to replace batteries and traditional power sources. In this review, the variety of techniques for scavenging energies from sustainable sources such as solar, air, waste heat, and surrounding mechanical forces are discussed that exploit the fascinating properties of 2D nanomaterials. In addition, practical applications of these fabricated power generating devices and their performance as an alternative to conventional power supplies are discussed with the future pertinence to solve the energy problems in various fields and applications.

Design and Performance of a Diaphragm Free-Piston Stirling Engine for Power Production From Low-Temperature Heat Sources

2018 ◽  
Author(s):  
Anas Nawafleh ◽  
Khaled R. Asfar
Keyword(s):  
Low Temperature ◽  
Waste Heat ◽  
Engine Performance ◽  
Surface Friction ◽  
Stirling Engine ◽  
Operating Conditions ◽  
Physical Parameters ◽  
Free Piston ◽  
And Performance ◽  
Free Piston Stirling Engine

This paper addresses modeling, design, and experimental assessment of a Gamma type low-temperature differential free-piston Stirling engine. The most advanced third-order design analysis method is used to model, simulate and optimize the engine. Moreover, the paper provides an experimental parametric investigation of engine physical parameters and operating conditions on the engine performance. The experimental test results are presented for a model validation, which shows about a 5% to 10% difference in the simulation results. The aim of this study is to design a Stirling engine capable of harvesting low-temperature waste heat effectively and economically and convert it to power. The engine prototype is designed to increase the engine performance by eliminating the main losses occurred in conventional Kinematic engines. Thus, elastic diaphragm pistons are used in this prototype to eliminate the surface friction of the moving parts, the use of lubricant, and to provide appropriate seals. In addition, flat plate heat exchangers, linear flexure bearing, a stainless-steel regenerator and a polyurethane displacer are outlined as the main components of the engine. Experiments successfully confirm the design models for output power and efficiency. Furthermore, it is revealed that the displacer-to-piston natural frequency ratio is an important design point for free-piston Stirling engines and should be addressed in the design for optimum power output.

scholarly journals Organic Rankine-Cycle Turbine Power Plant Utilizing Low Temperature Heat Sources

1980 ◽  
Author(s):  
V. Maizza
Keyword(s):  
Power Plant ◽  
Low Temperature ◽  
High Efficiency ◽  
Waste Heat ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Heat Sources ◽  
Operational Parameters ◽  
Working Fluids ◽  
Waste Energy

Utilizing and converting of existing low temperature and waste heat sources by the use of a high efficiency bottoming cycle is attractive and should be possible for many locations. This paper presents a theoretical study on possible combination of an organic Rankine-cycle turbine power plant with the heat pump supplied by waste energy sources. Energy requirements and system performances are analyzed using realistic design operating condition for a middle town. Some conversion systems employing working fluids other than water are being studied for the purpose of proposed application. Thermodynamic efficiencies, with respect to available resource, have been calculated by varying some system operating parameters at various reference temperature. With reference to proposed application equations and graphs are presented which interrelate the turbine operational parameters for some possible working fluids with computation results.

CFD Simulation of a Sliding Vane Expander Operating Inside a Small Scale ORC for Low Temperature Waste Heat Recovery

2014 ◽  
Author(s):  
Gianluca Montenegro ◽  
Augusto Della Torre ◽  
Angelo Onorati ◽  
Dalia Broggi ◽  
Gerd Schlager ◽  
...  
Keyword(s):  
Low Temperature ◽  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Cfd Simulation ◽  
Waste Heat ◽  
Small Scale

scholarly journals Design and Optimization of a Radial Inflow Turbine for Use with a Low Temperature ORC

Energies ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 8526
Author(s):  
Richard Symes ◽  
Tchable-Nan Djaname ◽  
Michael Deligant ◽  
Emilie Sauret
Keyword(s):  
Fuel Cell ◽  
Low Temperature ◽  
High Efficiency ◽  
Waste Heat ◽  
Fluid Dynamic ◽  
Organic Rankine Cycle ◽  
Pem Fuel Cells ◽  
Small Scale ◽  
Heat Sources ◽  
Radial Inflow Turbine

This study aims to design and optimize an organic Rankine cycle (ORC) and radial inflow turbine to recover waste heat from a polymer exchange membrane (PEM) fuel cell. ORCs can take advantage of low-quality waste heat sources. Developments in this area have seen previously unusable, small waste heat sources become available for exploitation. Hydrogen PEM fuel cells operate at low temperatures (70 °C) and are in used in a range of applications, for example, as a balancing or backup power source in renewable hydrogen plants. The efficiency of an ORC is significantly affected by the source temperature and the efficiency of the expander. In this case, a radial inflow turbine was selected due to the high efficiency in ORCs with high density fluids. Small scale radial inflow turbines are of particular interest for improving the efficiency of small-scale low temperature cycles. Turbines generally have higher efficiency than positive displacement expanders, which are typically used. In this study, the turbine design from the mean-line analysis is also validated against the computational fluid dynamic (CFD) simulations conducted on the optimized machine. For the fuel cell investigated in this study, with a 5 kW electrical output, a potential additional 0.7 kW could be generated through the use of the ORC. The ORC’s output represents a possible 14% increase in performance over the fuel cell without waste heat recovery (WHR).

Design of Small-Scale Radial Inflow Turbine Integrated into Organic Rankine Cycle

2012 ◽  
Vol 524-527 ◽  
pp. 3907-3913
Author(s):  
Hui Wang ◽  
Xin Ling Ma ◽  
Xin Li Wei
Keyword(s):  
Low Temperature ◽  
Flow Field ◽  
Simple Structure ◽  
High Efficiency ◽  
Waste Heat ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
3D Models ◽  
Small Scale ◽  
Radial Inflow Turbine

Organic Rankine Cycle (ORC) is dramatically suitable for low temperature waste-heat generation. The small-scale radial inflow turbine is introduced to integrate into the ORC characterized by simple structure, low parts count, high efficiency, especially getting high efficiency under the condition of smaller flow. This turbine is comprised of four main parts named by the volute, the nozzle (stator), the impeller (rotor), and the diffuser respectively. This paper introduces how to design and model the parts in detail, discusses modeling skills and shares experience. The structure of the volute and impeller is so complicated that parts are not easy to model. These 3D models can directly import to both ANSYS and FLUENT to analysis the flow field in order to achieve the optimize parameters.

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