Csaba Hetyei¹ and
Ferenc Szlivka<sup>2

1</sup>Óbuda University, Doctoral School on Safety and Security Sciences
  Budapest, Hungary
²Óbuda University, Donát Bánki Faculty of Mechanical and Safety Engineering
  Budapest, Hungary

INDECS 18(3), 389-399, 2020 DOI 10.7906/indecs.18.3.9 Full text available here.

Received: 11th March 2020. Accepted: 28th June 2020. Regular article

ABSTRACT
General energy demand is continuously increasing due to the fact that wind turbines and other renewable energy sources have begun to appear in previously unexplored areas, such as on the roofs of buildings. In view of this demand, a new type of wind turbines described in this article could become one of the energy generating tools in a smart grid system. In this article, first conventional and unconventional wind turbines are reviewed with respect to efficiency. Then a Counter Rotating Dual Rotor Wind Turbine (CO-DRWT) construction is analysed with Computational Fluid Dynamics (CFD) codes considering a fixed radial and a variable axial distance. In the analysis, power coefficients were calculated for different configurations. It was found that in case of the dual rotor wind turbine, the optimal axial distance for half diameter radial shift was in the range of 0,2 - 0,25 diameter.