ISSN Online: 2688-7231
ISBN Online: 978-1-56700-524-0
Proceedings of the 26thNational and 4th International ISHMT-ASTFE Heat and Mass Transfer Conference December 17-20, 2021, IIT Madras, Chennai-600036, Tamil Nadu, India
RADIATIVE TRANSFER ANALYSIS OF ROOFTOP SOLAR CHIMNEY BY TREATING MOIST AIR AS PARTICIPATING MEDIA
This study aims to develop a mathematical model of a solar
chimney considering air as a participatory medium for a
rooftop solar chimney. Steady-state heat transfer equations
were derived for glass, the air between glass and absorber
plate and for absorber wall separately. These equations were
then solved by the matrix method using the Gauss-Seidel
iteration approach in the in-house developed MATLAB code.
The in-house code was validated with simulation studies from
the literature. Relative humidity quantifies the absorbing
characteristic of humid air. Initially, to study the variation of the mass flow rate through the solar chimney as a function of relative humidity, heat transfer to air was considered to be via radiation alone to quantify the contribution from radiation
alone by making convective heat transfer coefficients zero.
There was a 10% to 12% increase in air flow rate with 50% relative humidity, compared to air with 10% relative humidity when the insolation varies between 500 W/m2 to 750 W/m2. Thus, moist-air as a participatory media should be considered while developing mathematical models. The developed mathematical model for solar chimney considering moist air as participating media (along with convection terms) and with turbulent co-relation for Nusselt number better predicted the overall result. And finally, the effect of absorptivity of absorber wall on the chimney performance is also presented.