I asked Satec some technical questions about their unique turbine design, and below is their response. Please bear in mind that as they say "funding is a problem". This is so true. throughout the world governments are more likely to help fund research on the improvements of proven wind technologies, where there is a great deal of production data and performance evaluations available. New ideas sometimes don't get the attention that they deserve. The venturii action of the sail system is however a very old concept. Used in persia before the birth of Christ.
Offered by Jay.
Satec Pty Ltd wrote:
Thank you for your enquiry, we are still a research and development company at this stage. We have trialled a number of prototypes, however, we are not commercialised as we have had trouble getting financial support in our country. Australian politicians talk alot about renewable technologies but do relatively little. This may well be a universal condition, however, I know that in the USA much has and still is being done on the technology front. You may appreciate that because we haven't commercialised our product that we won't release statistics into the internet world. The main reason for this is that construction and fabrication technology changes the output efficiency of the turbine quite considerably. Also our turbine is able to have multilevel blade stacking configurations, which means output can vary by that alone. At the moment our smaller units are around 4 kw and trialled with various generators mostly from other turbine manufacturers. I have enclosed a bit more descriptive information and will keep you on our database to update you as stats are available on product.
Regards, Peter Jansson.
Satec Wind Turbine Research & Development Notes
Satec was derived from Sail Advantaged Technologies. The Sail System runs on its own monorail track and is completely independent of the verticle stack of turbine blades. The sail system works by redirecting incident wind into the turbine, creating lift at the opening between the primary and secondary sails. The sail system also shields the turbine from drag it would normally experience in it's counter or windward rotation . The low pressure area behind the sails also assists in wind flow displacement, a very crucial issue in performance.
One of the main features with the Satec turbine design is to allow and promote wind flow characteristics through the turbine. If too much wind is stopped by the turbines presence a pressure zone is created and wind impacting on this pressure zone diverts and so lessens the availability of the energy resource. By maintaining and preserving volumetric efficiency, more energy is available to the turbine in it's efficient operation. The Sail system also allows us to choose where the incident wind is directed. The position of wind pressure from the Sail system can be focused further toward the inner part of the turbine creating higher RPM and greater flow through. As well as this the Sail system contributes to providing an additional 60 degrees of front blade lift. Our turbine blades get lift as any curved surface does with wind passing over it at the right angle of incidence, this lift force is very significant and contributes highly to the torque output. The effect of a pressure zone together with turbulence problems is what conventional horizontal axis wind turbine manufacturers are finding is restricting their performance achievements. The Satec turbine has better pressure zone management and less turbulence. The torque characteristics are very high with this design of turbine and this is further compounded by the Sail System.
A number of venturii actions are employed within the operation of both the Sail system and the turbine blade configuration. The intentions are to maximise "flow through" characteristics and increase internal pressures at the center of the turbine. An indication of the turbines aerodynamic qualities is that in operation it is very quiet. The turbine blades make no audible noise at wind speeds between 3mtrs sec up to 9 mtrs sec. The framework supporting the turbine contributes to some wind noise after 9 mtrs sec, however, we are working to reduce these structure related wind noises and don't consider them in any way a problem. Energy delivery is available from 3 mtrs per second wind speed. A recent design concept may allow these turbines to be built to supply 250Kw - 500Kw which would place them with existing large Horizontal Axis Wind Turbines. Wind farm applications would then be quite feasible with much less noise than present turbines.