Novel stair-shaped ground absorber for performance enhancement of solar chimney power plant

The present study investigates the use of a stair-shaped ground surface of a chimney-based solar thermal power plant (SCPP). The stair-shaped absorber is implemented to augment the efficacy of SCPP. The current investigation is conducted with a finite volume method-based solver, considering turbulent flow and solar irradiation models. Thermo-hydraulic performance, power generation, and irreversibility production of the plant are analyzed for different dimensions of the stair-shaped absorber. The present computing model is validated against the Manzaranes pilot plant with good agreement. The analysis indicates that the proposed stair-shaped absorber can improve power generation by up to - 80% (compared to a flat ground absorber surface). The power generation of a classical plant can be enhanced from 51 to 92 kW. The sloped ground absorber (a limiting case with infinite steps) generates 82 kW power, which is - 19% less than the stepped ground absorber surface. The role of geometric dimensions of the stair-shaped absorber is systematically examined. It reveals an increasing central height or number of steps of the absorber improves overall plant efficiency. However, the net exergy efficiency does not increase significantly with stair height, despite the rise in chimney exergy efficiency. Mathematical correlations for predicting power generation and different efficiencies are also developed. Thus, this work provides comprehensive insights into the potential of a stair-shaped absorber, and the findings suggest that the proposed ground absorber of a stair shape could be an alternative solution for improving power generation in classical SCPPs.