Comments on: Bird-Friendly Saphonian Wind Turbine Ditches Blades for a More Efficient, Less Expensive Design http://inhabitat.com/the-saphonian-wind-turbine-ditches-blades-for-a-more-efficient-and-less-expensive-design/ Green design & eco innovation for a better world Thu, 23 May 2013 21:03:05 +0000 hourly 1 http://wordpress.org/?v=abc By: Early Ehlinger http://inhabitat.com/the-saphonian-wind-turbine-ditches-blades-for-a-more-efficient-and-less-expensive-design/comment-page-1/#comment-431214 Early Ehlinger Thu, 20 Dec 2012 18:24:10 +0000 http://inhabitat.com/?p=455704#comment-431214 So here is the patent. If I understand it correctly (and I may not) It looks like the wind blowing on the device will change its angle of attack, thereby making it "want" to shift angles from the continued presence of the wind. The back side is connected to some hydraulic cylinders so that the constant shifting of angles will in theory increase the hydraulic pressure. That pressure is then used to drive a generator. Interesting concept - not sure that it will be any less maintenance-prone than a wind turbine or actually more efficient, though. Would be fun to put one next to a traditional windmill inside a wind tunnel and compare results. http://patentscope.wipo.int/search/en/detail.jsf?docId=WO2012039688&recNum=25&docAn=TN2010000005&queryString= So here is the patent. If I understand it correctly (and I may not) It looks like the wind blowing on the device will change its angle of attack, thereby making it “want” to shift angles from the continued presence of the wind. The back side is connected to some hydraulic cylinders so that the constant shifting of angles will in theory increase the hydraulic pressure. That pressure is then used to drive a generator. Interesting concept – not sure that it will be any less maintenance-prone than a wind turbine or actually more efficient, though. Would be fun to put one next to a traditional windmill inside a wind tunnel and compare results.

http://patentscope.wipo.int/search/en/detail.jsf?docId=WO2012039688&recNum=25&docAn=TN2010000005&queryString=

]]> By: Larry Gilman http://inhabitat.com/the-saphonian-wind-turbine-ditches-blades-for-a-more-efficient-and-less-expensive-design/comment-page-1/#comment-397467 Larry Gilman Fri, 16 Nov 2012 19:09:14 +0000 http://inhabitat.com/?p=455704#comment-397467 WBrooke on Betz limit claim: "This has to do with the fluid dynamics of the air passing through the device rather than the design of the device itself." The Betz limit is calculated for a turbine: i.e., any flow-through device. But the Saphonia device is not a turbine: the air flows around it, not through it, tipping the "sail" through a knot path. Ultimately of course the question of efficiency ceiling will boil down to reproducible demonstrations of hardware -- but where there is zero fuel cost, conversion "efficiency" is not a fundamental issue anyway. It all comes down to levelized $ per kilowatt-hour. If they win on this they win, period. This remains to be seen. The graveyard of brilliant ideas is well-populated. WBrooke on Betz limit claim: “This has to do with the fluid dynamics of the air passing through the device rather than the design of the device itself.” The Betz limit is calculated for a turbine: i.e., any flow-through device. But the Saphonia device is not a turbine: the air flows around it, not through it, tipping the “sail” through a knot path. Ultimately of course the question of efficiency ceiling will boil down to reproducible demonstrations of hardware — but where there is zero fuel cost, conversion “efficiency” is not a fundamental issue anyway. It all comes down to levelized $ per kilowatt-hour. If they win on this they win, period. This remains to be seen. The graveyard of brilliant ideas is well-populated.

]]> By: Brent Jarvis http://inhabitat.com/the-saphonian-wind-turbine-ditches-blades-for-a-more-efficient-and-less-expensive-design/comment-page-1/#comment-397284 Brent Jarvis Sun, 11 Nov 2012 11:50:26 +0000 http://inhabitat.com/?p=455704#comment-397284 The article doesn't say how much wind is needed for it to work or what would happen in case of extreme wind events. Before I would invest in this, I would have to see it work and put it thru several of my own tests.......... The article doesn’t say how much wind is needed for it to work or what would happen in case of extreme wind events. Before I would invest in this, I would have to see it work and put it thru several of my own tests……….

]]> By: Dmitry Podogov http://inhabitat.com/the-saphonian-wind-turbine-ditches-blades-for-a-more-efficient-and-less-expensive-design/comment-page-1/#comment-397184 Dmitry Podogov Wed, 07 Nov 2012 07:20:49 +0000 http://inhabitat.com/?p=455704#comment-397184 They say this turbine goes beyond the Betz limit... Looks like it doesnt need the air stream to flow THROUGH the turbine, it needs the wind just to put a pressure on it, like on a sail.. They say this turbine goes beyond the Betz limit… Looks like it doesnt need the air stream to flow THROUGH the turbine, it needs the wind just to put a pressure on it, like on a sail..

]]> By: WBrooke http://inhabitat.com/the-saphonian-wind-turbine-ditches-blades-for-a-more-efficient-and-less-expensive-design/comment-page-1/#comment-397160 WBrooke Tue, 06 Nov 2012 16:45:01 +0000 http://inhabitat.com/?p=455704#comment-397160 This seems like a dubious claim. The theoretical limit to the efficiency of any device that extracts energy from the wind is called the Betz Limit, which is 16/27, or 59.3%. This has to do with the fluid dynamics of the air passing through the device rather than the design of the device itself. Think of it this way...if you extracted 100% of the energy from a stream of air, then it would have zero momentum upon leaving the device and air would essentially "pile up" behind the rotor (more correctly the stream tube after the rotor would have to expand to infinite radius). The best you can do is extract 59.3% of the energy from the air stream. Maybe the Saphonian designers mean 80% of the Betz Limit? This seems like a dubious claim. The theoretical limit to the efficiency of any device that extracts energy from the wind is called the Betz Limit, which is 16/27, or 59.3%. This has to do with the fluid dynamics of the air passing through the device rather than the design of the device itself. Think of it this way…if you extracted 100% of the energy from a stream of air, then it would have zero momentum upon leaving the device and air would essentially “pile up” behind the rotor (more correctly the stream tube after the rotor would have to expand to infinite radius). The best you can do is extract 59.3% of the energy from the air stream. Maybe the Saphonian designers mean 80% of the Betz Limit?

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