Experimental comparison of solar chimney and energy tower systems for clean power generation

Abstract The growing demand for clean and sustainable energy underscores the importance of developing innovative solar technologies for large-scale power generation. Among them, solar chimney systems and energy towers have emerged as promising solutions. This study presents a laboratory-scale experimental comparison of these two systems, focusing on airflow velocity, collector geometry, humidification rate, tower/chimney height, response time, and optimal turbine placement. The experiments were conducted using an indoor laboratory-scale test rig under fully controlled temperature, humidity, and simulated solar radiation conditions to ensure a reliable comparison of the two systems. The results indicate that the performance of the solar chimney is highly dependent on collector geometry; replacing a circular collector with a square one increased airflow velocity by up to 245% and enhanced kinetic energy at the base nearly 11-fold. Furthermore, a 233% increase in solar radiation in the square collector led to a 53.8% rise in airflow velocity, compared with only 28.6% for the circular collector. In contrast, the energy tower demonstrated the unique ability to operate at night, with its performance improving by 62.7% under solar radiation compared to nighttime conditions. Its efficiency was found to be governed more by the humidification rate than by tower height. Additionally, the energy tower exhibited a response time three times faster than the solar chimney, highlighting its superior adaptability to changing conditions. For both systems, the lower section of the tower/chimney was identified as the optimal turbine location, where airflow velocity was maximized. These findings provide an experimental foundation for the optimization of solar chimney and energy tower systems and offer practical insights into selecting the most suitable technology under diverse climatic conditions.