Design and Testing of a Novel Building Integrated Cross Axis Wind Turbine

Abstract

Abstract:The prospect of harnessing wind energy in urban areas is not promising owing to low wind speeds and the turbulence caused by surrounding obstacles. However, these challenges can be overcome through an improved design of wind turbine that can operate efficiently in an urban environment. This paper presents a novel design of a building integrated cross axis wind turbine (CAWT) that can operate under dual wind direction, i.e., horizontal wind and vertical wind from the bottom of the turbine. The CAWT consists of six horizontal blades and three vertical blades for enhancing its self-starting behavior and overall performance. The study employed a mock-up building model with gable rooftop where both of the developed CAWT and the conventional straight-bladed vertical axis wind turbine (VAWT) are mounted and tested on the rooftop. The height of the CAWT and the VAWT above the rooftop was varied from 100 to 250 mm under the same experimental conditions. The results obtained from the experimental study showed that there is significant improvement in the coefficient of power (C p ) and self-starting behavior of the building integrated CAWT compared to the straight-bladed VAWT. At 100 mm height, the C p,max value of the CAWT increased by 266%, i.e., from 0.0345 to 0.1263, at tip speed ratio (TSR) (λ) of 1.1 and at wind speed of 4.5 m/s. Similar improvements in performance are also observed for all condition of CAWT heights above the rooftop where the CAWT outperformed the straight-bladed VAWT by 196%, 136% and 71% at TSR of 1.16, 1.08, and 1.12 for Y = 150, 200, and 250 mm, respectively. Moreover, the CAWT performs better at 10 • pitch angle of the horizontal blade compared to other pitch angles.

Preliminary Performance Tests and Simulation of a V-Shape Roof Guide Vane Mounted on an Eco-Roof System

“…performance is slightly higher than that of the VAWT integrated with a double slope roof at low TSRs (below 0.44). In the presence of the VRGV, the flow along the blades can effectively increase the lift force which increases the torque, thus improves the power output of the wind turbine [48]. This experiment shows that the design of a VRGV has a significant effect on improving the power performance of the VAWT mounted on a double slope roof.…”

“…The alternating current (AC) from the generator is rectified into a direct current (DC) for the current measurement in this experiment. In the present experiment, the frictional loss caused by the generator is negligible [48]. In this study, the rotor shaft was connected by a tapered roller bearing and a deep groove ball bearing [49].…”

“…In this experiment, the wind flow was produced by a series of ventilation fans that were arranged in a 3 × 3 equally spaced configurations, refer to Figure 11a. The wind direction is set to be parallel to the ground and perpendicular to the building model [48]. The air blown by these ventilation fans can reproduce similar turbulence and swirling flow in the field environment.…”

“…Energies 2018, 11, x FOR PEER REVIEW 10 of 33 building model [48]. The air blown by these ventilation fans can reproduce similar turbulence and swirling flow in the field environment.…”

“…The measurement was conducted using a dynamometer controller ( Figure 13) [48]. The alternating current (AC) from the generator is rectified into a direct current (DC) for the current measurement in this experiment.…”