Experimental study of the effects of the geometrical configurations on the performance of a small prototype solar chimney power plant with sensible heat storage

Purpose The purpose of this study is to experimentally investigate the effects of geometrical configurations specifically the height of the sensible heat storage tank and the collector-air channel gap on the thermal performance of a small-scale prototype solar chimney power plant (SCPP). By analyzing temperature distribution, airflow characteristics, and heat storage efficiency under controlled conditions, the study aims to identify optimal design parameters that enhance system efficiency and ensure extended operation during periods of low or no solar radiation. The findings are intended to support the development of more efficient, cost-effective and scalable SCPP systems for decentralized renewable energy generation, particularly in remote and arid regions. Design/methodology/approach A parametric study was conducted to investigate the effects of two key geometrical parameters on the thermal performance of the small-scale SCPP prototype: the height of water in the storage tank (hw), which determines the thermal mass and heat storage capacity, and the vertical gap between the absorber plate and the collector cover (hc), which influences airflow and convective heat transfer. The values tested were hw = 1, 6, 11 cm and hc = 2, 5, 9 cm. Throughout the study, these two parameters were consistently considered as the primary variables affecting the system performance. Findings The experimental results revealed that the height of the water in the sensible heat storage tank significantly influences the thermal performance of the solar chimney system, with an optimal water height of 6 cm yielding the highest temperatures at the chimney inlet and outlet, thus enhancing heat transfer and airflow. Increasing water height generally improved heat retention and absorber surface temperature, while too little or excessive water reduced efficiency due to limited thermal mass or stratification effects. Conversely, increasing the collector height (air gap) led to lower temperatures throughout the system, as a larger gap weakened natural convection and increased heat losses. The study demonstrated that optimizing these geometrical parameters can substantially improve thermal energy storage effectiveness and overall system performance in small-scale SCPPs. Originality/value This study provides an original experimental investigation into the combined effects of geometrical configurations and sensible heat storage on a small-scale SCPP prototype, a topic scarcely addressed in previous research. By systematically analyzing how water tank height and collector gap influence thermal performance under controlled conditions, the work offers novel insights into optimizing design parameters for enhanced energy storage and airflow dynamics. The findings contribute valuable practical guidelines for developing efficient, cost-effective and scalable SCPP systems, advancing their viability for decentralized renewable energy generation in remote and resource-limited regions.