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The Stirling engines are being carried out worldwide, used for divers’ application such as solar generator, micro cogeneration and cryogenic uses. The present paper is an over view of Stirling technologies researches. Several possibilities of resolving technical challenges encountered when manufacturing or using Stirling machines will be discussed. The most appropriate models and optimizations strategies are reported. Stirling engine performances are derived as function of geometric parameters (swept volumes, dead volumes, heat exchange areas, compression ratio…) for several working conditions (speed, mean pressure, temperature difference and working fluid). The effect of each parameter on the Stirling performances when using numerical and/or experimental approaches are presented. It is concluded that multi-objective optimizations methods are useful for predicting geometric and working parameters that corresponding to the optimal performances of the Stirling engine. [ABSTRACT FROM AUTHOR]

The Stirling machine has many successful applications mainly thanks to its high efficiency, fast cool-down, small size, light weight, low power consumption and high reliability (heating and cooling). A Beta type Stirling refrigerator is studied experimentally and numerically. The mathematical model takes into account complex phenomena related to compressible fluid mechanics, thermodynamics and heat transfer losses. A special attention is paid to the effect of geometric parameters such as dead and swept volumes respectively in compression and expansion spaces. Regenerator length, diameter and porosity are also discussed and optimal parameters are proposed. The effect of speed on the cold end temperature and refrigerator's performances is also investigated. Net cooling capacity, input power and COP were estimated at different conditions. Results allow understanding the physical processes occurring in the refrigerator and for predicting its performance. [ABSTRACT FROM AUTHOR]

In this work a numerical model was developed to optimize a kinematic Gamma Stirling engine. In this model thermal and mechanical losses are included to approximate experimental results. The influences of three operation parameters (filling pressure (3, 5, 10 bar), hot end temperature (300, 400, 500 °C) and rotation speed (160, 360, 600 rpm)) as well as heat exchangers efficiencies on the Stirling engine performances are studied. The studied parameters are dependent and their interactions are significant for the Stirling engine brake power. For high initial filling pressure, the brake power became more sensitive to the rotation speed and the hot end temperature. The set of operation parameters giving the optimal brake power will be presented and discussed. It was found that the performances of the engine are more sensitive to its regenerator efficiency. For ε r = 0.5 the output brake power and the Carnot efficiency were dropped respectively of 16% and 5% relatively to ε r = 1. [ABSTRACT FROM AUTHOR]