Increasing the Energy Density and Power Ratio of a Staggered VAWT Wind Farm by Using the Rotor's Diameter as a Reference

The development of wind energy systems has achieved a higher technology readiness level for Horizontal Axis Wind Turbine (HAWT). Unfortunately, the HAWT is only suitable for high wind speed areas. The Vertical Axis Wind Turbine (VAWT) is considered the ideal model to utilize wind energy in the low wind speed region. However, VAWT has a lower power coefficient. Therefore, developing a VAWT wind farm can improve the overall energy density for power generation in the low wind speed region. In this study, staggered configuration for three turbine clusters is evaluated through numerical simulation and experimental tests. The pitch distance is set by using the rotor's diameter as a reference for placing the 3rd rotor at the second row. The turbulence intensity in the area wake superposition is highly affected by the position of the 3rd rotor. The flow characteristic indicates that the 3D layout has a high concentration at the front area of the 3rd rotor. It leads to higher achievement of power ratio for the clusters. The overall power ratio for 3D layout can achieve more than 0.9, whereas, at a speed 3 m/s, the highest power ratio is obtained at 1.0. The finding in this study can be set as an essential reference for developing a VAWT wind farm with a specific arrangement and improving the overall power density of the turbine clusters.