| Solar chimneys convert solar energy into kinetic energy to generate electrical power or passively heat buildings. Air is driven through a solar chimney by the buoyancy created through the temperature difference between the heated air in the collector at the base of the tower and the ambient air at the tower exit.;In this study, solar chimney performance is numerically modeled. Current models have considered water bags and natural earth as means to store daytime thermal energy for nighttime operation of the system. The present model considers in-channel pebble bed thermal storage. A one-dimensional, implicit time stepping numerical model is developed to predict solar chimney performance throughout a 24 hour period.;The developed model is partially verified with available experimental data. Solar chimney geometry configurations are varied to study their impact on system performance. The daily energy, daily efficiency and heat transfer characteristics of the solar chimney with pebble bed thermal storage are summarized. The numerical simulation showed that introducing a pebble bed into the collector greatly increased solar chimney production during the night. Nightly exit velocities reach 40% of the peak daytime velocity when the pebble bed is introduced. However, the daily kinetic energy delivered by a solar chimney with pebble bed thermal storage is much less than a traditional solar chimney, suggesting pebble bed thermal storage is more practicable in building heating applications as opposed to power generation. |
