Experimental Investigation of the Effect of Collector Profile, Tower Diameter and Tower Height on the Performance of Small-Scale Solar Updraft Power Generator

Abstract

The performance of a small-scale solar updraft power generator is experimentally investigated under the effects of collector profile, tower diameter and tower height. The updraft velocity and temperature are measured from a total of 36 experiment cases. The current study's objective is investigating the optimum configuration that produces maximum updraft velocity and mechanical power output. The highest average updraft velocity of 1.22 m/s was recorded in experiment case number A-20. The highest average mechanical power of 12.35 mW is produced by experiment case number A-24. Both the collector height and tower diameter have optimum ranges that result in maximum updraft velocity and mechanical power. Increasing the collector height is bounded by heat losses in the collector and lowering the collector height is limited by the friction force where the airflow entrance is restricted. Having a larger tower diameter could have a negative effect on system performance. This situation was observed in experiment case number A-11 where increasing the tower diameter leads to a reduction of both updraft velocity and mechanical power. Since increasing the tower height always results in increased mechanical power, the collector height must be carefully matched with the tower diameter for a given tower height.