scholarly journals Development of a 100-Watt-Scale Beta-Type Low Temperature Difference Stirling Engine Prototype

2021 ◽  
Vol 313 ◽  
pp. 08004
Author(s):  
Matthias Lottmann ◽  
Zachary de Rouyan ◽  
Linda Hasanovich ◽  
Steven Middleton ◽  
Michael Nicol-Seto ◽  
...  
Keyword(s):  
Low Temperature ◽  
Stirling Engine ◽  
Geometry Compression ◽  
Working Space ◽  
Piston Seal ◽  
Stirling Engines ◽  
Charge Pressure ◽  
Shaft Power ◽  
Cylindrical Working ◽  
Gas Volume

This paper documents the ongoing design process of a Stirling engine prototype for a source temperature of 95 °C, aiming to achieve shaft power on the order of 100 Watts. The engine will serve to produce experimental data for the validation of a numerical low temperature Stirling model. The higher-level motivation is to assess the technical and economical potential of producing power from abundant sources of low temperature heat by using Stirling engines. Design decisions are governed by the goals of minimizing energy losses and maximizing the variability of operating points through variable heat exchanger geometry, compression ratio and charge pressure. The resulting design is a beta engine with a total gas volume around 100 liters. It features displacer and power pistons in a combined cylindrical working space and a mechanism using pivoting links similar to a bellcrank. The stroke of the power piston is adjustable while maintaining a constant top dead center position. A component critical for friction is the power piston seal, for which a low friction rolling seal and a conventional sliding seal were considered. As of June 2021, the development is at an advanced state and the first set of components are entering production.

scholarly journals Experimental evaluation of piston motion modification to improve the thermodynamic power output of a low temperature gamma Stirling engine

2021 ◽  
Vol 313 ◽  
pp. 04002
Author(s):  
Michael Nicol-Seto ◽  
David Nobes
Keyword(s):  
Low Temperature ◽  
Power Output ◽  
Stirling Engine ◽  
Maximum Power ◽  
Piston Motion ◽  
Heat Engines ◽  
Stirling Engines ◽  
Thermodynamic Performance ◽  
Engine Power ◽  
The Ideal

Stirling engines are a variety of heat engines which are capable of using heat from various sources including low temperature renewables. This work examines performance of a lab scale low temperature gamma type Stirling engine with a drive train modified with oval elliptical gears. The gears were added to dwell the engine piston motion to attempt to improve the thermodynamic performance of the engine by better replicating the ideal Stirling cycle. A variety of dwelling piston configurations were tested on both the displacer and power piston. It was observed that that the piston dwelling had the anticipated effect of changing the engine indicator diagrams to more closely resemble the ideal cycle, however there were no substantial improvements to maximum engine power. It was observed that dwelling the displacer piston caused substantial reductions to engine running speeds and resulted in maximum power being reduced. In the case of power piston dwelling the indicator diagram was enlarged and there were slight increases to maximum power production. Overall the added complexity of dwelled piston motion systems is not likely an advantageous method of increasing the power output of low temperature difference Stirling engines.

scholarly journals Investigation of effect of heat exchanger size on power output in low-temperature difference Stirling engines

2021 ◽  
Vol 313 ◽  
pp. 03002
Author(s):  
Linda Hasanovich ◽  
David Nobes
Keyword(s):  
Heat Exchanger ◽  
Low Temperature ◽  
Power Output ◽  
Heat Exchangers ◽  
Waste Heat ◽  
Significant Loss ◽  
Stirling Engine ◽  
Dead Volume ◽  
Optimal Geometry ◽  
Stirling Engines

The Stirling engine is capable of converting any source of thermal energy into kinetic energy, which makes it an attractive option for utilizing low-temperature sources such as geothermal or waste heat below 100 °C. However, at these low temperatures, the effects of losses are proportionally higher due to the lower thermal potential available. One such significant loss is excess dead volume, wherein a significant contributor is the heat exchangers. The heat exchangers must be selected to optimize power output by minimizing the dead volume loss while maximizing the heat transfer to and from the engine. To better understand what the optimal geometry of the heat exchanger components is, a Stirling engine is modelled using a third-order commercial modelling software (Sage) and trends of engine properties of power, temperature, and pressure for different heat exchanger geometries are observed. The results indicate that there is an optimum heat exchanger volume and geometry for low temperature Stirling engines. This optimum is also affected by other engine properties, such as regenerator size and engine speed. These results provide insight into the optimal geometry of these components for low-temperature Stirling engines, as well as providing design guidance for future engines to be built.

The Study of Medium/Low-Temperature Stirling Engine Power Output Characteristics

2013 ◽  
Vol 860-863 ◽  
pp. 1431-1435
Author(s):  
Wei Dong Sun ◽  
Qi Fen Li ◽  
Lin Hui Zhao ◽  
Li Fei Song ◽  
Xin Zhao
Keyword(s):  
Low Temperature ◽  
Power Output ◽  
Waste Heat ◽  
Thermal Power ◽  
Stirling Engine ◽  
Low Grade ◽  
Working Chamber ◽  
Charge Pressure ◽  
Output Characteristics ◽  
Engine Power

Stirling engine has the characteristics of diversification of heat source and high thermal power conversion efficiency. It has broad application prospects in using low-grade energy, such as solar energy, biomass emergy and industrial waste heat. In this paper, Schmidt Method used in the Stirling engine working cycle is analyzed theoretically, and the Stirling engine power output is calculated. The effects of temperature and the average cycle pressure on the output characteristics of the system are analyzed. Theoretical calculations show that the output characteristics can be improved significantly by adjusting the heating temperature and the average cycle pressure. An experiment station is then designed and constructed for the research on Stirling engine power output characteristics. Experimental results show that by improving pre-charge pressure in the working chamber with low temperature conditions, the system can achieve higher power output and thermal efficiency. Pre-charge pressure in the working chamber is adjusted to 2MPa, when the heater tube wall temperature reaches 650 °C, the output power exceeds 1750W, and the effective efficiency will be 23.3%.

scholarly journals A Theoretical and Experimental Study of Moderate Temperature Alfa Type Stirling Engines

Energies ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1622 ◽  
Author(s):  
Jacek Kropiwnicki ◽  
Mariusz Furmanek
Keyword(s):  
High Efficiency ◽  
Waste Heat ◽  
Heating Temperature ◽  
Mechanical Energy ◽  
Stirling Engine ◽  
Moderate Temperature ◽  
Heat Sources ◽  
Stirling Engines ◽  
Charge Pressure ◽  
Further Development

The Stirling engine is a device that allows conversion of thermal energy into mechanical energy with relatively high efficiency. Existing commercial designs are mainly based on the usage of high temperature heat sources, whose availability from renewable or waste heat sources is significantly lower than that of moderate temperature sources. The paper presents the results of experimental research on a prototype alpha type Stirling engine powered by a moderate temperature source of heat. Obtained results enabled calibration of the evaluated theoretical model of the Stirling engine. The model of the engine has been subsequently used for the analysis of regenerator effectiveness influenced by the charge pressure and the heating temperature. Performed study allowed to determine further development directions of the prototype engine to improve its power and efficiency. As a result of optimization, worked out design will potentially increase the indicated efficiency up to 19.5% (5.5% prototype) and the indicated power up to 369 W (114 W prototype).

Stirling Engines Powered by Renewable Energy Sources

2016 ◽  
Vol 831 ◽  
pp. 263-269
Author(s):  
Jacek Kropiwnicki ◽  
Aleksandra Szewczyk
Keyword(s):  
Renewable Energy ◽  
Low Temperature ◽  
Electric Power ◽  
Mechanical Energy ◽  
Renewable Energy Sources ◽  
Electrical Energy ◽  
Stirling Engine ◽  
Working Fluid ◽  
Energy Sources ◽  
Stirling Engines

Stirling engine is a device that produces mechanical energy using heat from any source of energy, without the need of combustion of any fuel inside the device. Renewable energy sources, which are mostly low-temperature energy sources, can be used to produce mechanical and electrical energy in Stirling engines. The paper presents an overview of the existing prototype Stirling engines designed for using of low-temperature energy sources, including renewable energy sources. Commercial devices for electric power generation offered for use in home, usually do not exceed 1 kW. Using the Schmidt model, the analyze of influence of temperature working fluid in the expansion space (heater) on the efficiency and the electric power generated in the Stirling engine of alpha type has been presented in the paper.

Thermodynamic Analysis of Solar Low-Temperature Differential Stirling Engine Considering Imperfect Regeneration and Thermal Losses

2020 ◽  
Vol 142 (5) ◽  
Author(s):  
Siddharth Ramachandran ◽  
Naveen Kumar ◽  
Mallina Venkata Timmaraju
Keyword(s):  
Low Temperature ◽  
Radiation Heat Transfer ◽  
Stirling Engine ◽  
Energy Utilization ◽  
Working Fluid ◽  
Temperature Differential ◽  
Transfer Coefficients ◽  
Plate Temperature ◽  
Stirling Engines ◽  
Coefficient Corrélation

Abstract Low-temperature differential Stirling engines (LTDSE) are the gamma-type Stirling engines that can produce useful work from source temperatures less than 350 K, making them a preferred choice/device for solar energy utilization. An improved mathematical model to evaluate the performance of the solar-operated LTDSE has been developed by incorporating the top heat loss coefficient correlation with the finite-time thermodynamic model of the Stirling engine. In order to realize the internal imperfections of the thermodynamic Stirling cycle, the effect of the imperfect regeneration process is incorporated. Input parameters such as absorber plate temperature, irradiation, and geometrical features of the solar LTDSE are taken from real-time experimental data available in the literature. The effect of convective and radiation heat transfer coefficients of working fluid on maximum power output and thermal efficiency is determined to be significant and marginal, respectively. A comprehensive study of various working fluids and regenerator materials is carried out to investigate their impact on the performance of solar LTDSE. Helium is the best-working fluid, among air, hydrogen, ethane, and nitrogen for the considered model. Copper exhibited maximum regenerator effectiveness compared with Monel 400, aluminum, SS-304L.

Stirling Engine Technology for Parabolic Dish-Stirling System Based on Concentrating Solar Power (CSP)

2015 ◽  
Vol 785 ◽  
pp. 576-580 ◽  
Author(s):  
Liaw Geok Pheng ◽  
Rosnani Affandi ◽  
Mohd Ruddin Ab Ghani ◽  
Chin Kim Gan ◽  
Jano Zanariah
Keyword(s):  
High Efficiency ◽  
Combustion Engine ◽  
Renewable Energy Sources ◽  
Stirling Engine ◽  
Energy Sources ◽  
Heat Engines ◽  
Stirling Engines ◽  
Parabolic Dish ◽  
Mechanical Devices ◽  
And Control

Solar energy is one of the more attractive renewable energy sources that can be used as an input energy source for heat engines. In fact, any heat energy sources can be used with the Stirling engine. Stirling engines are mechanical devices working theoretically on the Stirling cycle, or its modifications, in which compressible fluids, such as air, hydrogen, helium, nitrogen or even vapors, are used as working fluids. When comparing with the internal combustion engine, the Stirling engine offers possibility for having high efficiency engine with less exhaust emissions. However, this paper analyzes the basic background of Stirling engine and reviews its existing literature pertaining to dynamic model and control system for parabolic dish-stirling (PD) system.

scholarly journals Recovery of Exhaust Waste Heat for ICE Using the Beta Type Stirling Engine

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Wail Aladayleh ◽  
Ali Alahmer
Keyword(s):  
Internal Combustion Engine ◽  
Waste Heat ◽  
Combustion Engine ◽  
Internal Combustion ◽  
Stirling Engine ◽  
Gas Temperature ◽  
Ic Engine ◽  
Exhaust Waste Heat ◽  
Useful Power ◽  
Shaft Power

This paper investigates the potential of utilizing the exhaust waste heat using an integrated mechanical device with internal combustion engine for the automobiles to increase the fuel economy, the useful power, and the environment safety. One of the ways of utilizing waste heat is to use a Stirling engine. A Stirling engine requires only an external heat source as wasted heat for its operation. Because the exhaust gas temperature may reach 200 to 700°C, Stirling engine will work effectively. The indication work, real shaft power and specific fuel consumption for Stirling engine, and the exhaust power losses for IC engine are calculated. The study shows the availability and possibility of recovery of the waste heat from internal combustion engine using Stirling engine.

Optimization of Stirling Engine Performance Based on Multipoint Approximation Technique

1994 ◽  
Author(s):  
Vassili V. Toropov ◽  
Henrik Carlsen
Keyword(s):  
Computing Time ◽  
Engine Performance ◽  
Stirling Engine ◽  
Optimization Techniques ◽  
Approximation Technique ◽  
Working Cycle ◽  
Design Variables ◽  
Stirling Engines ◽  
Multipoint Approximation ◽  
Conventional Optimization

Abstract The ideal Stirling working cycle has the maximum obtainable efficiency defined by Carnot efficiency, and highly efficient Stirling engines can therefore be built, if designed properly. To analyse the power output and the efficiency of a Stirling engine, numerical simulation programs (NSP) have been developed, which solve the thermodynamic equations. In order to find optimum values of design variables, numerical optimization techniques can be used (Bartczak and Carlsen, 1991). To describe the engine realistically, it is necessary to consider several tens of design variables. As even a single call for NSP requires considerable computing time, it would be too time consuming to use conventional optimization techniques, which require a very large number of calls for NSP. Furthermore, objective and constraint functions of the optimization problem present some level of noise, i.e. can only be estimated with a finite accuracy. To cope with these problems, the multipoint explicit approximation technique is used.

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