Comparative studies on performance of solar towers with variable scale ratios

Area of Science:

• Renewable Energy
• Aerodynamics
• Thermal Engineering

Background:

• Solar towers are crucial for concentrated solar power (CSP) systems.
• Optimizing solar tower geometry can improve energy capture efficiency.
• Previous designs often lack aerodynamic sophistication.

Purpose of the Study:

• To investigate the impact of solar tower and collector geometry on aerodynamic performance.
• To identify optimal configurations for maximizing power output in solar towers.
• To enhance the efficiency of solar energy collection through geometric modifications.

Main Methods:

• Computational Fluid Dynamics (CFD) simulations and experimental testing were employed.
• Three scale models (1:60, 1:70, 1:122) of solar towers were analyzed.
• Hot-wire anemometry measured peak velocity at the collector-tower junction in open atmosphere conditions.

Main Results:

• Modified tower geometries (semi-divergent, fully divergent) were tested against straight towers.
• Collector geometries included flat, inclined, and semi-divergent designs.
• The fully divergent tower paired with a semi-convergent collector yielded the highest power output.

Conclusions:

• Area convergence in the tower and collector design is key to increasing peak velocity.
• The optimal configuration (divergent tower, semi-convergent collector) achieved a 54% power output increase over a cylindrical tower with a flat collector.
• Geometric optimization offers a significant pathway to enhance solar tower efficiency for concentrated solar power.