The Influence of Construction Parameters on the Thermal Efficiency and Indicated Power of a Stirling Engine

2019 ◽  
Author(s):  
Vinicius Sousa ◽  
Lohanna Paiva ◽  
Alexandre Zuquete Guarato
Keyword(s):  
Thermal Efficiency ◽  
Stirling Engine

scholarly journals Optimisation of a Quasi-Steady Model of a Free-Piston Stirling Engine

Energies ◽  
2018 ◽  
Vol 12 (1) ◽  
pp. 72 ◽  
Author(s):  
Ayodeji Sowale ◽  
Edward Anthony ◽  
Athanasios Kolios
Keyword(s):  
Power Systems ◽  
Thermal Efficiency ◽  
Waste Heat ◽  
Stirling Engine ◽  
Design Parameters ◽  
Free Piston ◽  
Output Performance ◽  
Free Piston Stirling Engine ◽  
External Combustion ◽  
Work Done

Energy from waste heat recovery is receiving considerable attention due to the demand for power systems that are less polluting. This has led to the investigation of external combustion engines such as the free-piston Stirling engine (FPSE) due to its ability to generate power from any source of heat and, especially, waste heat. However, there are still some limitations in the modelling, design and practical utilisation of this type of engine. Modelling of the FPSE has proved to be a difficult task due to the lack of mechanical linkages in its configuration, which poses problems for achieving stability. Also, a number of studies have been reported that attempt to optimise the output performance considering the characteristics of the engine configuration. In this study the optimisation of the second-order quasi-steady model of the gamma-type FPSE is carried out using the genetic algorithm (GA) to maximise the performance in terms of power output, and considering the design parameters of components such as piston and displacer damper, geometry of heat exchangers, and regenerator porosity. This present study shows that the GA optimisation of the RE-1000 FPSE design parameters improved its performance from work done and output power of 33.2 J and 996 W, respectively, with thermal efficiency of 23%, to 44.2 J and 1326 W with thermal efficiency of 27%.

Improving the Efficiency of Stirling Engines for Use in Solar Distributed Electricity, Heating, and Cooling

2013 ◽  
Author(s):  
Travis M. Schubert ◽  
Shirin Jouzdani ◽  
Kevin P. Hallinan
Keyword(s):  
Heat Exchanger ◽  
Thermal Efficiency ◽  
Effective Means ◽  
Heat Engine ◽  
Stirling Engine ◽  
Future Application ◽  
Film Material ◽  
Expansion Chamber ◽  
Thermal Switch ◽  
Low Mass

Limiting solar power is the inability to cost effectively store energy. The most cost effective means to store solar energy is thermally in the ground, which can then be used for direct conversion to electricity. However, doing so is limited by a historically poor thermal efficiency of such engines. A novel Stirling engine is posed which more closely mimics a Carnot heat engine. It does this through the use of a new passive thermal ‘switch’ which permits heat flow into the expansion chamber of the Stirling engine only when the temperature of the chamber is above a desired value. Ideally heat would be added only at the end of the compression stroke and the beginning of the expansion stroke. Central to this thermal switch is the use of a vanadium dioxide (VO2) low mass heat exchanger internal to the expansion chamber. This low mass heat exchanger allows the film material to track and react to the temperature changes within the expansion chamber, permitting it to transfer heat only when needed. An adiabatic model of this enhanced solar Stirling engine is developed. Results indicate that the thermal efficiency can be nearly doubled, delivering a second law efficiency of over 0.6. Further, a year round overall efficiency accounting for losses in the Stirling engine and solar thermal collectors of 7% appears to be feasible when this engine is integrated with ground solar storage, providing the necessary power to meet loads in a low energy residence. Such results demonstrate promise for future application of this technology.

Thermal Model of the EuroDish Solar Stirling Engine

2007 ◽  
Vol 130 (1) ◽  
Author(s):  
Francisco J. García Granados ◽  
Manuel A. Silva Pérez ◽  
V. Ruiz-Hernández
Keyword(s):  
Experimental Data ◽  
Thermal Efficiency ◽  
Thermal Model ◽  
Stirling Engine ◽  
Good Qualitative Agreement ◽  
Parabolic Dish ◽  
Engine System ◽  
Work Model ◽  
Main Components ◽  
Comparison With Experimental Data

One parabolic dish—Stirling engine system—has been in operation at the Engineering School of Seville since March 2004. The unit, based on the Eurodish system, is one of the several Country Reference Units of the EnviroDish project. The system has achieved a maximum thermal efficiency (solar to electricity) close to 20% during operation. The analysis of the different parameters suggests a high potential for improvement. A thermal model of the main components of the engine package (cavity, receiver, and Stirling engine) can help to evaluate possible modifications of the system and identify the most promising ones. The development of such a thermal model and its comparison with experimental data gathered during this period are reported in this work. Model results exhibit a good qualitative agreement with the available measurements. However, the validation of the model will require measuring more parameters at the cavity, receiver, and engine.

First and second law analysis of a Stirling engine with imperfect regeneration and dead volume

2009 ◽  
Vol 223 (11) ◽  
pp. 2595-2607 ◽  
Author(s):  
J Harrod ◽  
P J Mago ◽  
K Srinivasan ◽  
L M Chamra
Keyword(s):  
Entropy Generation ◽  
Thermal Efficiency ◽  
Engine Performance ◽  
Stirling Engine ◽  
Dead Volume ◽  
Second Law ◽  
Work Output ◽  
Volume Percentage ◽  
Stirling Cycle ◽  
Second Law Analysis

This article discusses the thermodynamic performance of an ideal Stirling cycle engine. This investigation uses the first law of thermodynamics to obtain trends of total heat addition, net work output, and thermal efficiency with varying dead volume percentage and regenerator effectiveness. Second law analysis is used to obtain trends for the total entropy generation of the cycle. In addition, the entropy generation of each component contributing to the Stirling cycle processes is considered. In particular, parametric studies of dead volume effects and regenerator effectiveness on Stirling engine performance are investigated. Finally, the thermodynamic availability of the system is assessed to determine theoretical second law efficiencies based on the useful exergy output of the cycle. Results indicate that a Stirling engine has high net work output and thermal efficiency for low dead volume percentages and high regenerator effectiveness. For example, compared to an engine with zero dead volume and perfect regeneration, an engine with 40 per cent dead volume and a regenerator effectiveness of 0.8 is shown to have ∼60 per cent less net work output and a 70 per cent smaller thermal efficiency. Additionally, this engine results in approximately nine times greater overall entropy generation and 55 per cent smaller second law efficiency.

A Mathematical Model for the Stirling Engine Cycle

1981 ◽  
Vol 103 (3) ◽  
pp. 505-510 ◽  
Author(s):  
E. W. Beans
Keyword(s):  
Mathematical Model ◽  
Dead Space ◽  
Thermal Efficiency ◽  
Stirling Engine ◽  
Design Parameters ◽  
The Mathematical Model ◽  
Engine Cycle ◽  
Good Agreement

A mathematical model for the Stirling engine cycle is presented. This model differs from the Schmidt Cycle in that an adiabatic dead space is assumed and that the enthalpy exchange between various volumes is accounted for. The model, in general, predicts performance which is lower than the Schmidt Cycle. The model results in a thermal efficiency which is a function of all design parameters rather than temperature only. A comparison between the p-ν diagram from the mathematical model and a measured diagram is in good agreement.

Valved Heat Engine Working on Modified Atkinson Cycle

2010 ◽  
Vol 132 (1) ◽  
Author(s):  
C. V. Ramesh
Keyword(s):  
Thermal Efficiency ◽  
Heat Engine ◽  
Engine Performance ◽  
Inertial Force ◽  
Expansion Ratio ◽  
Stirling Engine ◽  
Performance Criteria ◽  
Stirling Cycle ◽  
Heat Engines ◽  
Atkinson Cycle

There is immense scope for the development of heat engines that can directly convert solar and biochemical renewable sources of thermal energy to high-grade energy. Regenerative Stirling cycle heat engine with its performance criteria of highest thermal efficiency and high mean effective pressure is theoretically the best engine for small capacity reciprocating heat engine. However, the practical Stirling engine performance is far from the ideal. As an alternative, practical heat engines based on thermodynamic cycles (without regeneration) other than the Stirling cycle have been suggested. This paper deals with a new concept in the design of reciprocating heat engine working on modified Atkinson cycle. In the Atkinson cycle, expansion ratio being higher than compression ratio, the thermal efficiency is better than that of the standard Otto cycle. Heat engine design based on the suggested modified Atkinson cycle can be an alternative to the practical Stirling engine. In the conceptual mechanical design of the engine suggested here, apart from utilizing the principle of Atkinson cycle for achieving higher thermal efficiency, the mechanical configuration of the reciprocating engine ensures a high degree of inertial force balancing. This can result in reduced vibrations in the mountings of the power units.

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