Enhancement of solar chimney performance by passive vortex generator

Abstract

According to the global consensus on mitigation of greenhouse gas and human footprint as well as improvement of industrial sustainability by the exploitation of renewable energy, the mission of this study dedicated to the performance enhancement of planar solar chimneys in converting much more solar radiation into air enthalpy by vortex generation technique. For this purpose, a passive vortex generator (VG) as an inexpensive but effective approach is employed for the enhancement of heat transfer. The well-developed commercial software of COMSOL Multiphysics was used for two-way modeling and simulation of sophisticated fluid-solid interaction in transient turbulent natural convection heat transfer phenomena. An extensive comparison has been made between two configurations of solar chimney namely with and without VG. According to the numerical results, the natural vibration of elastic VG induces moving vortices into the flow field which is also responsible for the enhancement of natural convection heat transfer by mixing and reducing the thermal boundary layer. Moreover, the VG significantly improves ΔToutlet up to 300% and also decreases the temperature of the absorber surface more than 50% which is under constant heat flux. Both of these factors lead to higher performance for natural air heater.