A Method of Decreasing Power Output Fluctuation of Solar Chimney Power Generating Systems
ABSTRACT Severe fluctuation of power output is a common problem in the various generating systems of renewable energies. The hybrid energy storage system with water and soil is adopted to decrease the fluctuation of solar chimney power generating systems in the present research. The mathematical models of fluid flow, heat transfer and power output features of solar chimney power generating systems including collector, chimney and energy storage layer have been established, also the influence of the material and depth of energy storage medium upon power output has been analyzed. The simulation results demonstrate that hybrid energy storage system with water and soil can effectively decrease the power output fluctuation. When the depth of water layer is less than 0.1 m, the increase of the depth would decrease the variance of day-night air temperature and velocity in the system, and the power output in daytime would largely decease and that at night largely increase. The ratio between peak and valley of power output thus would largely decrease. When the depth of the water layer is more than 0.1 m, the increase of the depth would cause relatively slight power output and change range.