Energy and exergy analysis of the airflow inside a solar chimney

Sustainable development is closely associated with the use of renewable energy resources. In order to achieve a viable development, from an environmental point of view, the energy efficiencies of processes can be increased using renewable energy resources. There is also a correlation between exergy and sustainable development, since exergy is consumed or destroyed due to irreversibilities. The solar chimney has been highlighted in studies of using solar energy to generate electric power. In this paper, the energy and exergy analyses of the airflow inside a solar chimney are presented. Using experimental data obtained in a prototype, the first and second laws of thermodynamics were used to estimate the amounts of energy and exergy lost to the surroundings and the exergetic efficiency. The dead state was defined using two different reference temperatures. The results show that the exergy losses were lower and the efficiency was higher for the lowest ambient temperature used as the dead state temperature, when compared to the instantaneous ambient temperature.