Status of activities
The Passive Variable Geometry (PVG) patent features of the Windcity Vertical Axis Wind Turbine are being optimized for Urban Boundary Layer and building-specific applications thanks to a specially developed non-linear transient simulation Python code including Galileian relativity mechanics and integrated into the workflow of upcoming experimental tests.
The findings demonstrate a nearly ~400% acceleration performance of the proposed PVG concept compared to fixed geometry rotors in the start-up region of the turbine, up to a critical point imposed by balancing centrifugal forces.
Acceleration [rad/s2] versus tip-speed ratio [-] in low (left = 3m/s) and mx edium (right =5m/s) wind speeds: gray = base-line fixed geometry rotor, blue/green = 2 choices of parameters from the proposed PVG system; the results include Galileian relativity calculations and the variation of the tensor of inertia for the PVG rotors.
R&D and design of the turbine proceed by organically taking into account safety themes & risk analyses requested by the harmonisation of the Machinery EU Directive 2006/42/CE and the International Electrotechnical Committee 61400-2 code: rotor, generator, shutdown & protection system, direct & indirect support structures are being designed and prototyped accordingly.
The focus and ambition is the ability to connect directly with any commercial solar inverter, to enhance building integration features, and is yet part of the preliminary tests on the power converter prototype: results with 2 commercial 2.0 kW inverters indicated a possible blocking feature preventing integration of the power train.
Strategic experimental installation of the PVG rotor in Torbole, Garda Lake Italy 2020
Future steps:
Therefore, a firmware modification in the wind power converter is under development for final tests, to implement a general voltage-current limit curve suitable for the PV string case.
Experimental laboratory tests on the VAWT fully operational are being prepared with the construction of a homebuilt wind tunnel facility integrated with a measurement and data acquisition system. The system allows to measure aerodynamic, mechanical, power electronics variables and to perform overall performance tests.
The flow fitting properties of a special axial fan and other components are being assessed via computational fluid dynamics (CFD), in order to operate the wind tunnel according to the testing constraints. Data acquisition system has been designed, procured and assembled in order to allow the final KPIs assessment.
The built wind tunnel facilities and axial fan optimization studies