Letter of Support for WHI’s VAWT Wake Research Proposal

As consultant for Iopara Inc., I collaborated with WHI on their prior project, Modeling Blade Pitch and Solidities in Straight Bladed VAWTs, funded through the CEC’s Energy Innovations Small Grant Program. For that research project, Iopara created an aerodynamic model of WHI’s vertical axis wind turbine using data collected from a 3-turbine array located in Palm Springs, CA. Iopara’s modeling validated the “coupled vortex effect” and predicted that the physics and wind effects the phenomenon generated by certain configurations of turbines would be able to significantly increase the energy output of lower solidity VAWTs such as WHI’s G168.
WHI’s proposed Applied Research and Development project will test these predictions, confirming the increase in Capacity Factor that can be realized by the strategic positioning of a VAWT near its neighbor. The project will further build on the findings of the previous study in order to develop a commercially viable strategy for deployment of VAWTs in the understories of existing horizontal axis wind turbines. Although our CEC funded study evaluated two dimensional wakes produced directly behind the VAWT array, our other work on VAWTs indicates that a region of turbulence will develop just above an array of closely spaced turbines. Above that, the increase in wind flowing over the top of the VAWT array will produce a region of wind moving faster than the incoming wind speed at that height. In order to take advantage of the speed-up effect, the VAWT arrays would need to be placed so that the HAWT rotors operate in the higher-speed wind zone without being impacted by the turbulent region.