Can Çinar

Construction and testing of a dish/Stirling solar energy unit

AbstractThis study is concerned with the construction of a simple solar energy conversion system consisting of a parabolic dish concentrator and a Stirling engine. For this purpose, a parabolic dish concentrator consisting of planar mirror segments was built and coupled with a Stirling engine recently developed by the authors for solar energy conversion and domestic cogeneration. By mounting the engine to the bottom of the dish concentrator, the solar rays were directly reflected onto the hot end of the displacer cylinder. For the design of an appropriate parabolic dish concentrator reflecting solar rays onto the hot zone of a displacer cylinder and satisfying their uniform distribution, an equation was derived. The energy conversion unit constructed was tested under 820 W m−2 solar radiation. The engine started to run at 93°C hot end temperature. At steady running conditions, the hot end temperature of the displacer cylinder became stable at ∼156°C. The variation of shaft power with engine speed and char...

Thermodynamic analysis of an α-type Stirling engine with variable phase angle

Abstract In this study, a variable phase angle, α-type Stirling engine was described and analysed from kinematic and thermodynamics point of view. Kinematic relations were described for the calculation of hot and cold cylinder volumes. The instantaneous temperature distribution of the working fluid, through the heating—cooling passages and regenerator, was calculated by preparing a nodal analysis in FORTRAN. Effect of phase angle variation on work generation was examined. By using three different convective heat transfer coefficient, which were 200, 300, and 400 W/m2 K, variation of work generation with working fluid mass was examined. For the same values of convective heat transfer coefficient, variation of engine power versus the engine speed was examined.

Design and manufacturing of a hermetic Stirling engine

In this study, design and manufacturing of a hermetic Stirling engine having rhombic-drive mechanism were presented. In the engine, rhombic-drive mechanism was used for less vibration and piston friction. An alternator was coupled with the rhombic-drive mechanism in the engine block to convert mechanical power directly into electricity. Due to the mechanical problems, engine performance was measured without alternator unit by coupling the rhombic-drive mechanism with a dynamometer. The tests were conducted at 400 ℃ and 500 ℃ hot-end temperatures at atmospheric pressure. The surface temperature of the displacer cylinder hot end was controlled by LPG flow. The maximum torque and power obtained were 1.26 Nm at 264 r/min engine speed and 41.7 W at 350 r/min engine speed, respectively, at 500 ℃ hot-end temperature. The variation of cyclic work obtained by the experimental study was compared with the theoretical results obtained by nodal analysis.