The Experts below are selected from a list of 5328 Experts worldwide ranked by ideXlab platform
Somchai Wongwises - One of the best experts on this subject based on the ideXlab platform.
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a four power piston low temperature differential Stirling Engine using simulated solar energy as a heat source
Solar Energy, 2008Co-Authors: Ancha Kongtragool, Somchai WongwisesAbstract:In this paper, the performances of a four power-piston, gamma-configuration, low-temperature differential Stirling Engine are presented. The Engine is tested with air at atmospheric pressure by using a solar simulator with four different solar intensities as a heat source. Variations in Engine torque, shaft power and brake thermal efficiency with Engine speed and Engine performance at various heat inputs are presented. The Beale number obtained from the testing of the Engine is also investigated. The results indicate that at the maximum actual energy input of 1378 W and a heater temperature of 439 K, the Engine approximately produces a maximum torque of 2.91 N m, a maximum shaft power of 6.1 W, and a maximum brake thermal efficiency of 0.44% at 20 rpm.
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performance of a twin power piston low temperature differential Stirling Engine powered by a solar simulator
Solar Energy, 2007Co-Authors: Bancha Kongtragool, Somchai WongwisesAbstract:Abstract This paper provides an experimental investigation on the performance of a low-temperature differential Stirling Engine. In this study, a twin power piston, gamma-configuration, low-temperature differential Stirling Engine is tested with non-pressurized air by using a solar simulator as a heat source. The Engine testing is performed with four different simulated solar intensities. Variations of Engine torque, shaft power and brake thermal efficiency with Engine speed and Engine performance at various heat inputs are presented. The Beale number, obtained from the testing of the Engine, is also investigated. The results indicate that at the maximum simulated solar intensity of 7145 W/m 2 , or heat input of 261.9 J/s, with a heater temperature of 436 K, the Engine produces a maximum torque of 0.352 N m at 23.8 rpm, a maximum shaft power of 1.69 W at 52.1 rpm, and a maximum brake thermal efficiency of 0.645% at 52.1 rpm, approximately.
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thermodynamic analysis of a Stirling Engine including dead volumes of hot space cold space and regenerator
Renewable Energy, 2006Co-Authors: Ancha Kongtragool, Somchai WongwisesAbstract:This paper provides a theoretical investigation on the thermodynamic analysis of a Stirling Engine. An isothermal model is developed for an imperfect regeneration Stirling Engine with dead volumes of hot space, cold space and regenerator that the regenerator effective temperature is an arithmetic mean of the heater and cooler temperature. Numerical simulation is performed and the effects of the regenerator effectiveness and dead volumes are studied. Results from this study indicate that the Engine net work is affected by only the dead volumes while the heat input and Engine efficiency are affected by both the regenerator effectiveness and dead volumes. The Engine net work decreases with increasing dead volume. The heat input increases with increasing dead volume and decreasing regenerator effectiveness. The Engine efficiency decreases with increasing dead volume and decreasing regenerator effectiveness.
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optimum absorber temperature of a once reflecting full conical concentrator of a low temperature differential Stirling Engine
Renewable Energy, 2005Co-Authors: Ancha Kongtragool, Somchai WongwisesAbstract:This paper provides a theoretical investigation on the optimum absorber temperature of a once-reflecting full conical concentrator for maximizing overall efficiency of a solar-powered low temperature differential Stirling Engine. A mathematical model for the overall efficiency of the solar-powered Stirling Engine is developed. The optimum absorber temperature for maximum overall efficiency for both limiting conditions of maximum possible Engine efficiency and maximum possible Engine power output is determined. The results indicated that the optimum absorber temperatures calculated from these two limiting cases are not significantly different. For a given concentrated solar intensity, the maximum overall efficiency characterized by the condition of maximum possible Engine power output is very close to that of the real Engine of 55% Carnot efficiency, approximately.
Mohammad Hossei Ahmadi - One of the best experts on this subject based on the ideXlab platform.
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artificial neural network ann pso and ann ica for modelling the Stirling Engine
International journal of ambient energy, 2016Co-Authors: S Toghyani, Mohammad Hossei Ahmadi, Alibakhsh Kasaeia, Ami H MohammadiAbstract:Nowadays, shortage of fossil fuels resources, especially oil, and also global attention to environmental hazards produced by the internal combustion process have caused extensive researches on the development of renewable energy Engine technology. Among all kinds of renewable resources, solar energy Stirling Engines have their own special situation for energy generation with lower pollutants and sustainable sources. The Stirling Engine is an external combustion Engine that uses any external heat source to generate mechanical power. Various parameters affect the performance of the Stirling Engine. In this study, artificial neural network (ANN) was applied to estimate the power and torque values obtained from a Stirling heat Engine (Philips M102C Engine). It employs the Levenberg–Marquardt algorithm for training ANN with back propagation network for estimating the power and torque of the Stirling heat Engine. The performances of the imperialist competitive algorithm (ICA)-ANN and ANN-particle swarm optimisa...
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optimisation of the thermodynamic performance of the Stirling Engine
International journal of ambient energy, 2016Co-Authors: Mohammad Hossei Ahmadi, Ami H Mohammadi, Mohse S PourkiaeiAbstract:In this communication, the thermodynamic performance of an ideal Stirling cycle Engine has been investigated. In this regard, the first law of thermodynamics has been employed to determine state of total heat addition, network output, and thermal efficiency with changes in dead volume percentage and regenerator effectiveness. Second law analysis is applied to obtain the trends for the total entropy generation of the cycle. Moreover, the entropy generation of each element involving the Stirling cycle processes is measured. Three objective functions including the output power per rate of mass of the ideal gas working fluid (wnet) and the thermal efficiency (ηt) have been considered simultaneously for maximisation, and the ratio of total entropy generation to rate of mass of the ideal gas working fluid of the Stirling Engine is minimised at the same time. Multi-objective evolutionary algorithms based on the NSGA-II algorithm have been employed, while effectiveness of the regenerator, effectiveness of low- an...
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connectionist intelligent model estimates output power and torque of Stirling Engine
Renewable & Sustainable Energy Reviews, 2015Co-Authors: Mohammad Hossei Ahmadi, Mohammad-ali Ahmadi, Seyed Abbas Sadatsakkak, Michel FeidAbstract:Stirling Engine is an Environmental friendly heat Engine which can reduce CO2 emission through combustion process. Various criteria should be considered for designing and optimizing Stirling heat Engines such as power, torque, and pressure loss in heat exchangers of Stirling Engine, efficiency and so forth. In the aforementioned criteria, output power and shaft torque are the most important criteria which represent the performance and efficiency of the Stirling Engines. So, determination of output power and shaft torque with low uncertainty and high precision are required. In this paper, a new generation of intelligent models named “least square support vector machine (LSSVM)” is employed to predict output power and shaft torque of Stirling Engines. To build, train and test the LSSVM model, various accurate experimental data from open literature are employed. The outputs of the LSSVM model are compared to experimental ones and statistical parameters of the LSSVM model including correlation coefficient, average absolute relative deviation (AARD) and root mean square error (RMSE) are calculated. According to the results obtained via LSSVM model, the LSSVM model can predict output power and shaft torque of Stirling heat Engine with reasonable and acceptable accuracy. Finally, the LSSVM model can help us in designing of Stirling Engine with low degree of uncertainty and high precision.
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using gmdh neural networks to model the power and torque of a Stirling Engine
Sustainability, 2015Co-Authors: Mohammad Hossei Ahmadi, Mohammad-ali Ahmadi, Mehdi Mehrpooya, Marc A RoseAbstract:Different variables affect the performance of the Stirling Engine and are considered in optimization and designing activities. Among these factors, torque and power have the greatest effect on the robustness of the Stirling Engine, so they need to be determined with low uncertainty and high precision. In this article, the distribution of torque and power are determined using experimental data. Specifically, a novel polynomial approach is proposed to specify torque and power, on the basis of previous experimental work. This research addresses the question of whether GMDH (group method of data handling)-type neural networks can be utilized to predict the torque and power based on determined parameters.
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multi objective optimization of Stirling Engine using non ideal adiabatic method
Energy Conversion and Management, 2014Co-Authors: S Toghyani, Alibakhsh Kasaeia, Mohammad Hossei AhmadiAbstract:Abstract In the recent years, remarkable attention is drawn to Stirling Engine due to noticeable advantages, for instance a lot of resources such as biomass, fossil fuels and solar energy can be applied as heat source. Great numbers of studies are conducted on Stirling Engines and non-ideal adiabatic method is one of them. In the present study, the efficiency and the power loss due to pressure drop into the heat exchangers are optimized for a Stirling system using non-ideal adiabatic analysis and the second-version Non-dominated Sorting Genetic Algorithm. The optimized answers are chosen from the results using three decision-making methods. The applied methods were compared at last and the best results were obtained for the technique for order preference by similarity to ideal solution decision making method.
Ancha Kongtragool - One of the best experts on this subject based on the ideXlab platform.
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a four power piston low temperature differential Stirling Engine using simulated solar energy as a heat source
Solar Energy, 2008Co-Authors: Ancha Kongtragool, Somchai WongwisesAbstract:In this paper, the performances of a four power-piston, gamma-configuration, low-temperature differential Stirling Engine are presented. The Engine is tested with air at atmospheric pressure by using a solar simulator with four different solar intensities as a heat source. Variations in Engine torque, shaft power and brake thermal efficiency with Engine speed and Engine performance at various heat inputs are presented. The Beale number obtained from the testing of the Engine is also investigated. The results indicate that at the maximum actual energy input of 1378 W and a heater temperature of 439 K, the Engine approximately produces a maximum torque of 2.91 N m, a maximum shaft power of 6.1 W, and a maximum brake thermal efficiency of 0.44% at 20 rpm.
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thermodynamic analysis of a Stirling Engine including dead volumes of hot space cold space and regenerator
Renewable Energy, 2006Co-Authors: Ancha Kongtragool, Somchai WongwisesAbstract:This paper provides a theoretical investigation on the thermodynamic analysis of a Stirling Engine. An isothermal model is developed for an imperfect regeneration Stirling Engine with dead volumes of hot space, cold space and regenerator that the regenerator effective temperature is an arithmetic mean of the heater and cooler temperature. Numerical simulation is performed and the effects of the regenerator effectiveness and dead volumes are studied. Results from this study indicate that the Engine net work is affected by only the dead volumes while the heat input and Engine efficiency are affected by both the regenerator effectiveness and dead volumes. The Engine net work decreases with increasing dead volume. The heat input increases with increasing dead volume and decreasing regenerator effectiveness. The Engine efficiency decreases with increasing dead volume and decreasing regenerator effectiveness.
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optimum absorber temperature of a once reflecting full conical concentrator of a low temperature differential Stirling Engine
Renewable Energy, 2005Co-Authors: Ancha Kongtragool, Somchai WongwisesAbstract:This paper provides a theoretical investigation on the optimum absorber temperature of a once-reflecting full conical concentrator for maximizing overall efficiency of a solar-powered low temperature differential Stirling Engine. A mathematical model for the overall efficiency of the solar-powered Stirling Engine is developed. The optimum absorber temperature for maximum overall efficiency for both limiting conditions of maximum possible Engine efficiency and maximum possible Engine power output is determined. The results indicated that the optimum absorber temperatures calculated from these two limiting cases are not significantly different. For a given concentrated solar intensity, the maximum overall efficiency characterized by the condition of maximum possible Engine power output is very close to that of the real Engine of 55% Carnot efficiency, approximately.
Sassi Be Nasrallah - One of the best experts on this subject based on the ideXlab platform.
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improvement of a non energy consuming system a gamma Stirling Engine
Environmental Engineering and Management Journal, 2016Co-Authors: Ramla Gheith, Fethi Aloui, Sassi Be NasrallahAbstract:In this paper, the classical adiabatic model was chosen. The assumption of perfect gas working fluid was replaced by that of a real gas working fluid. This last assumption was defined by the van der Waals state equation. A Gamma type Stirling Engine functioning with a maximum filling pressure of 10 bars was used to carry out experiments. Both theoretical models: the Perfect Gas Adiabatic Model (PGAM) and the Real Gas Adiabatic Model (RGAM) were applied to the Gamma Stirling Engine. The influence of the initial filling pressure on the Engine performance was studied numerically and experimentally. The real gas adiabatic model presents results closer to the experimental ones, especially for high initial filling pressure.
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determination of adequate regenerator for a gamma type Stirling Engine
Applied Energy, 2015Co-Authors: Ramla Gheith, Fethi Aloui, Sassi Be NasrallahAbstract:This paper deals with an optimization of the Stirling Engine regenerator’s. Firstly, different materials are experimented (Stainless Steel, Copper, aluminum and Monel 400). The Engine performances and the state of each material after 15h of use are considered. The Stainless steel was the material that best satisfies these two conditions. Five regenerators in stainless steel with different porosities were manufactured and experimented (95%, 90%, 85%, 80% and 75%). Porosity that gives the best trade-off between maximizing the Engine brake power, maximizing the heat transfer and minimizing the pressure drops, was retained. Thus, the regenerator in stainless steel with porosity of 85% was considered as the most suitable matrix maximizing the Stirling Engine performances and minimizing heat and friction losses.
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analysis and design consideration of mean temperature differential Stirling Engine for solar application
Renewable Energy, 2008Co-Authors: Iskander Tlili, Youssef Timoumi, Sassi Be NasrallahAbstract:This article presents a technical innovation, study of solar power system based on the Stirling dish (SD) technology and design considerations to be taken in designing of a mean temperature differential Stirling Engine for solar application. The target power source will be solar dish/Stirling with average concentration ratio, which will supply a constant source temperature of 320°C. Hence, the system design is based on a temperature difference of 300°C, assuming that the sink is kept at 20°C. During the preliminary design stage, the critical parameters of the Engine design are determined according to the dynamic model with losses energy and pressure drop in heat exchangers was used during the design optimisation stage in order to establish a complete analytical model for the Engine. The heat exchangers are designed to be of high effectiveness and low pressure-drop. Upon optimisation, for given value of difference temperature, operating frequency and dead volume there is a definite optimal value of swept volume at which the power is a maximum. The optimal swept volume of 75cm3 for operating frequency 75Hz with the power is 250W and the dead volume is of 370cm3.
Wen Lih Che - One of the best experts on this subject based on the ideXlab platform.
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a computational fluid dynamics study on the heat transfer characteristics of the working cycle of a β type Stirling Engine
Energy Conversion and Management, 2014Co-Authors: Jose Leo Salaza, Wen Lih CheAbstract:A compressible CFD code has been developed to study the heat transfer characteristics of a β-type Stirling Engine with a very simple design and geometry. The results include temperature contours, velocity vectors, and distributions of local heat flux along solid boundaries at several important time steps as well as variations of average temperatures, integrated rates of heat input, heat output, and Engine power. It is found that impingement is the major heat transfer mechanism in the expansion and compression chamber, and the temperature distribution is highly non-uniform across the Engine at any given moment. The results, especially the rates of heat transfer, are quite different from those obtained by a second-order model. The variations of heat transfer rates are much more complicated than the simple variations returned by the second-order model. This study sheds light into the complex heat transfer mechanism inside the Stirling Engine and is very helpful to the understanding of the fundamental process of the Engine cycle.
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a computational fluid dynamics study on the heat transfer characteristics of the working cycle of a low temperature differential γ type Stirling Engine
International Journal of Heat and Mass Transfer, 2014Co-Authors: Wen Lih Che, King Leung Wong, Yu Feng ChangAbstract:Abstract A three-dimensional compressible CFD code has been developed to study the heat transfer characteristics of a twin-power piston γ -type Stirling Engine. The results include temperature contours, velocity vectors, and distributions of local heat flux along solid boundaries at several important time steps as well as variation of average temperatures, integrated rates of heat input, heat output, and Engine power. It is found that Impingement is the major heat transfer mechanism in the expansion and compression chambers, and the temperature distribution is highly non-uniform across the Engine volume at any given moment. This study sheds light into the complex heat transfer mechanism inside the Stirling Engine and is very helpful to the understanding of the fundamental process of the Engine cycle.
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an experimental study on the performance of the moving regenerator for a γ type twin power piston Stirling Engine
Energy Conversion and Management, 2014Co-Authors: Wen Lih Che, King Leung Wong, Hung E CheAbstract:Abstract In this paper, a helium charge γ-type twin power piston Stirling Engine has been studied experimentally to understand the effects of several regenerator parameters on the overall performance of the Engine. The regenerator incorporated in this Engine is a moving regenerator which is housed inside the displacer of the Engine, and the parameters investigated include regenerator matrix material, matrices arrangement, matrix wire diameter, and fill factor. Stacked-woven metal screens have been used as regenerator matrix materials. The results include Engine shaft torque, power, and efficiency versus Engine speed at several Engine’s hot-end temperatures. It is found that all parameters pose significant impact on Engine performance. Copper is a superior regenerator material than stainless steel for the current Engine; regenerator matrix screens have to be installed in a manner that the working-gas-flow direction is normal to the surface of matrix screens; very small wire diameter results in large pressure drop and reduce regenerator effectiveness; and there exists an optimal fill factor. The study offers some important information for the design of moving regenerator in a γ-type Stirling Engine.
