Mathematical study on performance enhancement of solar updraft tower power plant by hot gas injection from an external source

In this paper, a theoretical model for simulation of a solar updraft tower power plant with the assumption of axisymmetric condition is developed to study the impact of hot gas injection at the chimney base as well as extraction of a portion of hot gas after the turbine and re-entered it at the collector inlet. A new computational code is written by Matlab software and the effects of operational parameters are studied. Results show that the maximum power output is increased by 49.9% by increasing the extraction fraction from 0% to 40% at a wind velocity of 10 m/s. Besides, the obtained results show that the power output is enhanced as the mass flow rate of hot gas increases. As a result, the maximum power output at a hot gas mass flow rate of 30 kg/s is approximately 37% higher than the one at a hot gas mass flow rate of 10 kg/s. Results reveal that the optimum performance of SUTPP takes place at the ratio of pressure drop across the turbine to driving pressure potential in the range from 0.83 to 0.87. Furthermore, the power output in the presence of wind is investigated and the positive influence of wind is illustrated. Results indicate that by increasing the wind velocity from 10 m/s to 30 m/s, the maximum power output is increased by 386.1%