Geometry Alteration Effect on a Solar-Wind Power System

The solar-wind power system consists of a solar collector part to collect and transfer solar energy to the working fluid and a chimney part to provide stack causing the fluid to flow continuously. The effects of geometries variation of the collector cover (canopy) and the chimney on the performance of the system are studied. The velocity, density, temperature and pressure distribution in the system are predicted in both, the collector and the chimney. The investigation was carried out by using numerical analysis based on the "Finite – Difference Technique" to solve iteratively the continuity, momentum, energy, and the stat equations under tow – dimensional flow assumption. Suitable assumptions have been used as an input to solve the governing equations under various solar intensities, ambient temperatures and wind speed, for four seasons in Baghdad city, to estimate the system performance during the year. Due to the nature of non parallel stream lines in the convergence or divergence passages, "Grid Generation and Axis Transformation Technique" was adopted to transfer the computational model from the physical to a computational plane.

The results showed that change of the canopy orientation in the solar collector have considerable effects on the performance of the system. The efficiency is increased in the diverging canopy case compared with the parallel case. The best flow characteristic is obtained with converging chimney, where, the flow accelerates towards the outlet of the chimney. This demonstrates the ability to shorten the chimney height, compared with the straight chimney case.

(Keywords: Renewable energy, Computational modeling, Solar chimney, Energy technology,).