Conceptual development of an energy recovery from the chimney flue gases using ducted turbine system

•Kinetic energy of the chimney flue gases has been extracted for power generation.•CFD simulation of 6-bladed ducted turbine system has been carried out.•Duct system increases the average flue gas velocity by 2 times the inlet velocity.•NACA4412 profile blade extracted maximum 34.91 kW from flue gases at 7° diffuser angle.•While NACA4416 profile blade generated maximum 34.74 kW power with 11° diffuser angle.

An innovative idea of extracting kinetic energy from man-made wind resources (chimney flue gases) with ducted horizontal axis turbine system for producing electricity is introduced in this paper. The turbine system is positioned beyond the chimney outlet, to avoid any negative impact on the chimney performance. The duct acts as a safety cover for the energy recovery system and also enhances the performance of the system. The effect of airfoils NACA4412 and NACA4416 on the power extraction by the energy recovery system using a 6-bladed ducted turbine has been studied using CFD simulation. It is observed that the average flue gas velocity in the duct section at the throat is approximately twice that of the inlet velocity, whereas maximum throat velocity achieved is 2.6 times the inlet velocity. The results from the CFD (Computational Fluid Dynamics) based simulations analysis indicate that a significant power can be harnessed from the chimney exhaust. The system may be retrofitted to existing chimneys of thermal power plants, refineries and other industries. The market potential for this energy recovery system appears to be very high due to abundant chimneys, cooling towers and other man-made air/gaseous exhaust system present globally.