Power augmentation of ducted wind turbines for urban structures: Experimental, numerical, and economic approaches

Abstract

Recent development in using wind turbines for urban areas results in inserting turbines inside buildings. As buildings' walls may act as a duct for the turbine, this study focuses on a ducted wind turbine with a fixed duct geometry. A method is organized for achieving the improved generated power and the wind speed augmentation with fixed geometry of duct regardless of the type of the turbine, which is the aim of building designers. Using a porous disc (PD) instead of a wind turbine rotor makes the study cost and time effective. PDs within a duct help estimate any given duct's maximum available power extraction capability. In addition, experimental and numerical tests examine the effect of PDs solidity on the performance of diffuser augmented wind turbines and the corresponding economic analysis. Both experimental and numerical results agree that the power coefficient highly depends on the solidities of the PD. The power coefficient of a ducted PD with a solidity of 0.3 is augmented by up to 30%. Nevertheless, in some cases, employing a duct can contribute to the power reduction if the solidity exceeds a critical value. A smoke visualization technique helps vortex study. Economic assessment of a ducted turbine for three scenarios belonging to Germany and Italy shows a 15.3% decline in cost per electricity production. The payback period decreases by 3.42 years, 7.68 months, and 6.36 months for Scenarios 1, 2, and 3.

Optimized configuration with economic evaluation for shrouded vertical axis wind turbines applicable for urban structures

“…These vortexes are separated after the diffuser. The vortex shedding results in oscillating velocity inside the rotor 14 . The vortices drop the wake's pressure and cause mass flow rate incrementation through the duct.…”

“…In addition, increasing the length of the flange enhanced the pressure difference between the front and back of the turbine, which ultimately improved the aerodynamic performance of the turbine. 14,24 Hashem and Mohamed 25 analyzed three different flat-panel, curved-surface, and cycloidal-surface shrouds. The cycloidal shroud had the highest power coefficient, but the overall cost was high because of its curved surfaces.…”

“…9,10 Wind energy production is proportional to the cube of wind speed ( wind passing through the turbine increases, there is a possibility of a significant increase in the output power of the turbine. One method to increase wind speed is to use a cover around the rotors, known as diffuser augmented wind turbines (DAWTs), shrouded turbines, 11,12 ducted turbines, 13,14 diffuser, 15 or wind-lens. 16 A cover around a rotor increases the inlet mass flow rate, creates low back pressure, and increases wind speed.…”

“…Jafari and Kosasih 11 studied the length and angle of a diffuser and mentioned that increasing the length and angle improves the rotor performance. In addition, increasing the length of the flange enhanced the pressure difference between the front and back of the turbine, which ultimately improved the aerodynamic performance of the turbine 14,24 . Hashem and Mohamed 25 analyzed three different flat‐panel, curved‐surface, and cycloidal‐surface shrouds.…”