Numerical Investigation of Convective-Radiative Heat Transfer in a Building-integrated Solar Chimney

Solar chimney can be a new technology to generate electrical power. The chimney consists of a converging channel with one vertical wall and one inclined wall. The analysis is carried out on a three-dimensional turbulent model by the commercial code Ansys-Fluent. The numerical analysis is intended to examine the effect of the glass wall inclination. Results are given in terms of wall temperature distributions, air velocity and temperature fields for a uniform wall heat flux on the vertical wall equal to 300 W/m2. Some numerical simulations are performed considering Solar irradiation in Naples (Italy). Thermal and fluid dynamics behaviours are evaluated in order to have some indications to improve the energy efficiency of the system. The better thermal performances for the same imposed heat flux are in correspondence to an inclination of 2 degrees whereas when Solar irradiation is considered the better performances are obtained at the greatest investigated inclination angle. Solar chimney is also convenient as regards with additional heat gains into the building in winter period. It can be estimated a heat gain in the range 8-12% of solar radiation entering the chimney for a thermal conductance equal to 2.0 W/m2K.