Author:
Suzuki Hiroki,Hasegawa Yutaka,Oluwasola O.D. Afolabi,Mochizuki Shinsuke
Abstract
Abstract
This study presents the impact of seasonal variation in air density on the operating tip-speed ratio of small wind turbines. The air density, which varies depending on the temperature, atmospheric pressure, and relative humidity, has an annual amplitude of about 5% in Tokyo, Japan. This study quantified this impact using the rotational speed equation of motion in a small wind turbine informed by previous work. This governing equation has been simplified by expanding the aerodynamic torque coefficient profile for a wind turbine rotor to the tip-speed ratio. Furthermore, this governing equation is simplified by using nondimensional forms of the air density, inflow wind velocity, and rotational speed with their characteristic values. In this study, the generator’s load is set to be constant based on a previous analysis of a small wind turbine. By considering the equilibrium between the aerodynamic torque and the load torque of the governing equation at the optimum tip-speed ratio, the impact of the variation in the air density on the operating tip-speed ratio was expressed using a simple mathematical form. As shown in this derived form, the operating tip-speed ratio was found to be less sensitive to a variation in air density than that in inflow wind velocity.
Subject
General Physics and Astronomy
Reference12 articles.
1. Experimental studies on the 8-kW horizontal axis wind turbine with variable speed control;Shimizu;Journal of Japan Wind Energy Association,1996
2. Studies on power augmentation of horizontal axis wind turbine with variable speed control;Shimizu;Journal of Japan Wind Energy Association,1998
3. Global estimations of wind energy potential considering seasonal air density changes;Ulazia;Energy,2019