Analysis and Design of a Giromill Type Vertical Axis Wind Turbine for a Low Wind Profile Urban Area A.Mohanasundaram 1 , Dr.P.Valsalal 2 , 1 Research Scholar, Department of Electrical and Electronics Engineering, Aalim Muhammed Salegh College of Engineering, Chennai-55, Email: mohanasundaram.a@aalimec.ac.in 2 Associate Professor, Department of Electrical and Electronics Engineering, College of Engineering, Anna University, Chennai-25, Email: valsalal@annauniv.edu Abstract: This paper analyses the design parameters of giromill type vertical axis wind turbine in QBlade and Mat lab Simulink software with an appropriate practical demonstration. The significant factors like Reynolds number, numbers of blades, aspect ratio, and wake module analysis were carried out to design a wind turbine to enhance maximum power at 2 m/s wind speed. The classical 4 digit symmetrical, unsymmetrical NACA series airfoil are taken to analyze Glide ratio with proposed D shaped airfoil and it produces high lift forces at low wind speed. Based on the significant results obtained a virtual VAWT model was constructed in a Simulink which endorses QBlade analysis results. Two VAWTs with an aspect ratio of 2.5 and 0.75 were constructed with 1kW PMDC generator to validate the simulation results. The results exhibit that the low aspect ratio of 0.75, odd number blades like 3 or 5 with D shaped airfoil enables to catch more downwind and it improves the VAWT model has maximum energy efficiency to 50.49 % more than the 2.5 high aspect ratio wind turbines. Keywords: Giromill, Glide ratio, Aspect ratio, Wake module analysis, Virtual VAWT model, PMDC generator. 1. Introduction A wind turbine is a machine used to convert the kinetic energy of wind into electrical energy. There are two types of a wind turbine which produce electrical energy from the wind: they are horizontal-axis wind turbine (HAWT) and vertical-axis wind turbine (VAWT). The VAWT has a growing interest in power generation nowadays because it is simple construction, low cost, self-starting at low wind speed. It always orients towards the wind direction means that it is capable of capturing wind from any direction and generates electrical energy at low wind speeds and do not require yaw mechanism [1-2]. Regular wind turbines operate wind speeds between 10 m/s to 25 m/s but small wind turbines have been designed to operate even at 2 m/s. It produces lower noise level only 27-37 dB, suitable for our living condition. The VAWT mounted lower to the ground making it easy for maintenance if needed and can build at locations on the taller structures, such as the horizontal type can’t. The VAWT located at the top of buildings as they do not suffer from changing wind direction and the simplicity of design produces better response even they face a turbulence flow [3]. The VAWT is mainly classified into two types; Savonius and Darrieus type. The Savonius turbine generates the electricity through the drag force but Darrieus wind turbine rotors are based on lift force. Two bladed Savonius turbine is more efficient than three blades Savonius with higher power coefficient under the same operating condition [4-5]. Darrieus turbine has more efficient power coefficient than the Savonius turbine at low wind speed but it suffers from the self-starting problem. Power coefficient of a hybrid turbine is 0.23 at low wind speed which is higher than the Savonius and Darrieus turbine [6]. The H type or Giromill type VAWTs are particularly well suited to residential wind power generation for some inherent advantages in comparing with their HAWT counterparts also it can withstand turbulent wind flow [7- 9]. The selection of the airfoil plays an important role in achieving better wind turbine aerodynamic performance. One attractive advantage of VAWTs is that the blades can have a constant shape along their length and, unlike HAWTs, there is no need in twisting the blade as every section of the blade is subjected to the same wind speed. This allows an easier design, fabrication and replication of the blade which can influence in a cost reduction and is one of the main reasons to design the wind turbine with this rotor configuration. The H type VAWTs uses, symmetric airfoils from the NACA 4-digit series like NACA0012, 0018, 0020 are commonly employed because only for these airfoils aerodynamic characteristics are the most well documented [10]. The aim of the recent researches is to maximize the annual Energy to optimize the power coefficient by suitable selection of blade profiles [11]. For a fixed cross-sectional area of the turbine, to optimize the curve of the power coefficient it is possible to use different airfoil sections and/or rotors with different aspect ratio because the VAWT that is much wider than tall is more efficient [12-13]. This discussion portrays why VAWT suitable for generating electrical energy for household application at rural and urban areas in a country like India which has huge potential and interest for the wind energy. The organization of the various section of this paper for the proposed work described in Fig 1.