Re: [Biofuel] Vertical axis wind turbines Another approach to wind
I may have fallen off the thread here-- are we still talking about th h.o.g.? I applaud the imagination of the h.o.g. developers. I'm sorry, they seem doomed to failure. Too much mass and serious doubts about the effectiveness of the design. Ernie Rogers In a message dated 11/24/04 5:58:14 AM Pacific Standard Time, [EMAIL PROTECTED] writes: The hours of operation aren't even close. The comparison is invalid. Incorrect as our coaches are running 16 hours a day and the loads on those turbine bears are nowhere near the loads on the drive shaft bearings behind the 200 hp motor. Chris. ___ Biofuel mailing list [EMAIL PROTECTED] http://wwia.org/mailman/listinfo.cgi/biofuel Biofuel at Journey to Forever: http://journeytoforever.org/biofuel.html Biofuel archives at Infoarchive.net (searchable): http://infoarchive.net/sgroup/biofuel/
Re: [Biofuel] Vertical axis wind turbines Another approach to wind
The bearings on the machine shown in the video were a problemactually it was not a bearing problem as much as it was an out of round problem for the bottom ring that flowed over the bearing. The company decided it was going to be a continuing critical issue so has gone back to their original design (from 9 predecessor prototype machines), of diverting the majority of the outer weight to a center axis point. The only outside bearings that will be in place will not be constant weight bearing points but will be more like guidewires for those occasions when high winds might be strong enough to flex the upper unit. Much of the design will remain the same and the units ability to operate multiple generators of any type will still be in place; there just won't be any friction points on the outside edges of the machine other than pressure sensitive type rollers that will provide the link for each generator in place, up to 400kW (or so is anticipated). As far as penciling out, it will, easily, but as everything else will depend on what terms you have (or have) to make with any utility company you might be working with; of course, if you are setting this up to replace a grid system on a retail basis you won't care what the utility wants. There are and will be many options for the use of this or any Wind system, now or in the future. This machine won't be produced to take the place of existing tower type turbines and, at this point, it would be foolish to think that; but, it certainly could be a co-existing partner where many of the tower turbines have been placed as this unit would cause no to very little deflection problem in most cases. Weight does not seem to be a big problem with this machine, however I certainly think they need to do additional RD on composite materials to reduce the weight, especially if it is going to be a free wheeling machine. If they can get the weight factor down to 10,000 to 15,000 pounds it will open many new doors for them. The big catch is to do it at a reasonable cost and comparative to what it is for steel (though who knows where that is going to go as it has doubled in the past year). Right now the 400kW model is expected to have a price of about $300,000; but again, it depends on material costs. Dave - Original Message - From: Chris Lloyd [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Monday, November 22, 2004 1:59 AM Subject: RE: [Biofuel] Vertical axis wind turbines Another approach to wind Elegance of design means simple. I would like to see a tally of wear points for this design plus fab costs. I doubt it will pencil. If the sealed grease bearings on my truck can be made to last 10 years I see no problem if it's built well enough. There is no reason these days to have short bearing life. Chris. --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.799 / Virus Database: 543 - Release Date: 19/11/2004 ___ Biofuel mailing list [EMAIL PROTECTED] http://wwia.org/mailman/listinfo.cgi/biofuel Biofuel at Journey to Forever: http://journeytoforever.org/biofuel.html Biofuel archives at Infoarchive.net (searchable): http://infoarchive.net/sgroup/biofuel/ ___ Biofuel mailing list [EMAIL PROTECTED] http://wwia.org/mailman/listinfo.cgi/biofuel Biofuel at Journey to Forever: http://journeytoforever.org/biofuel.html Biofuel archives at Infoarchive.net (searchable): http://infoarchive.net/sgroup/biofuel/
Re: [Biofuel] Vertical axis wind turbines Another approach to wind
automatically. If this is not the case please let me know. Kirk McLoren wrote: The hours of operation aren't even close. The comparison is invalid. Then there is the question of which bearings you refer to. Wheel bearings? Totally different application from moving the foils. The applied loads in that machine are very large. That makes the controls large which means expensive. The bottom line is mostly cost. I don't think that machine has anything new to offer in that area. It is new and novel. So what? Economics determine viability. Since it uses rigid foils I'm not sure it even has much advantage in the dead bird problem. Still not enthused. Kirk --- Chris Lloyd [EMAIL PROTECTED] wrote: Elegance of design means simple. I would like to see a tally of wear points for this design plus fab costs. I doubt it will pencil. If the sealed grease bearings on my truck can be made to last 10 years I see no problem if it's built well enough. There is no reason these days to have short bearing life. Chris. __ Do you Yahoo!? Meet the all-new My Yahoo! - Try it today! http://my.yahoo.com ___ Biofuel mailing list [EMAIL PROTECTED] http://wwia.org/mailman/listinfo.cgi/biofuel Biofuel at Journey to Forever: http://journeytoforever.org/biofuel.html Biofuel archives at Infoarchive.net (searchable): http://infoarchive.net/sgroup/biofuel/ ___ Biofuel mailing list [EMAIL PROTECTED] http://wwia.org/mailman/listinfo.cgi/biofuel Biofuel at Journey to Forever: http://journeytoforever.org/biofuel.html Biofuel archives at Infoarchive.net (searchable): http://infoarchive.net/sgroup/biofuel/
Re: [Biofuel] Vertical axis wind turbines Another approach to wind
automatic positioning requires controls be it a cam and a linkage or a motor and electronics. It doesn't mean an operator is on duty. Kirk --- Martin K [EMAIL PROTECTED] wrote: I don't think it has controls, I think they are positioned automatically. If this is not the case please let me know. Kirk McLoren wrote: The hours of operation aren't even close. The comparison is invalid. Then there is the question of which bearings you refer to. Wheel bearings? Totally different application from moving the foils. The applied loads in that machine are very large. That makes the controls large which means expensive. The bottom line is mostly cost. I don't think that machine has anything new to offer in that area. It is new and novel. So what? Economics determine viability. Since it uses rigid foils I'm not sure it even has much advantage in the dead bird problem. Still not enthused. Kirk --- Chris Lloyd [EMAIL PROTECTED] wrote: Elegance of design means simple. I would like to see a tally of wear points for this design plus fab costs. I doubt it will pencil. If the sealed grease bearings on my truck can be made to last 10 years I see no problem if it's built well enough. There is no reason these days to have short bearing life. Chris. __ Do you Yahoo!? Meet the all-new My Yahoo! - Try it today! http://my.yahoo.com ___ Biofuel mailing list [EMAIL PROTECTED] http://wwia.org/mailman/listinfo.cgi/biofuel Biofuel at Journey to Forever: http://journeytoforever.org/biofuel.html Biofuel archives at Infoarchive.net (searchable): http://infoarchive.net/sgroup/biofuel/ ___ Biofuel mailing list [EMAIL PROTECTED] http://wwia.org/mailman/listinfo.cgi/biofuel Biofuel at Journey to Forever: http://journeytoforever.org/biofuel.html Biofuel archives at Infoarchive.net (searchable): http://infoarchive.net/sgroup/biofuel/ __ Do you Yahoo!? The all-new My Yahoo! - Get yours free! http://my.yahoo.com ___ Biofuel mailing list [EMAIL PROTECTED] http://wwia.org/mailman/listinfo.cgi/biofuel Biofuel at Journey to Forever: http://journeytoforever.org/biofuel.html Biofuel archives at Infoarchive.net (searchable): http://infoarchive.net/sgroup/biofuel/
Re: [Biofuel] Vertical axis wind turbines Another approach to wind
It's all centrifugal force, the sails close with the aid of hydraulic (actually pneumatic) rams that are modified to take air in and ease it out depending upon what the sails are doing. As the unit receives more wind additional generators come on line and create additional leverage against the ring drive, helping slow the unit or keeping it from excessive speed. The sails also remain open if speeds start to get too fast which also helps create additional drag to maintain reasonable RPM's. Prototype units have been recorded operating in wind speeds in excess of 102mph without any ill effects on the unit itself or without cutting power production off. While this unit is very large, (compared to what I'm not sure), it certainly has some advantages in the maintenance area. It's low to the ground so most repairs to generators and their linkage take place at 10 feet or less (most of us that have moderate height fear can tolerate that), off the ground; if it's something structural it would be 30 feet or less. If a sail gets damaged (say from someone shooting at it and making it look like Swiss cheese), it can be easily replaced, usually within a few hours and by the owner or caretakerand that's only if a person really needed too. In reality you could have several of the sails damaged and the unit will still operate and produce power so one has the advantage of picking and choosing his/her own time to do any repairs. Most anything on this unit can be repaired by the owner/caretaker and normally could be done within a day or two as nearly all parts are available at your local builder supply/farm supply/auto parts stores. This machine has been designed to be extremely user friendly and they expect it to have a life cycle of at least 30 years. I've been told that in most cases they don't even want to talk to someone about purchasing their machine if they can't show them and pencil out a ROI in less than 6 yearspreferably 2.5 to 4 years. I understand the reservations about this design, just like anything else that seems a little radical; and I don't blame folks for their skepticism, but I'll stand by these guys and know that they are going to get this right and very soon. You can see them at their website: http://energytransfercorporation.com/ Sorry to be so wordy, just trying to make this as simple as possible. Dave - Original Message - From: Martin K [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Monday, November 22, 2004 5:04 PM Subject: Re: [Biofuel] Vertical axis wind turbines Another approach to wind I don't think it has controls, I think they are positioned automatically. If this is not the case please let me know. Do you Yahoo!? Meet the all-new My Yahoo! - Try it today! http://my.yahoo.com ___ Biofuel mailing list [EMAIL PROTECTED] http://wwia.org/mailman/listinfo.cgi/biofuel Biofuel at Journey to Forever: http://journeytoforever.org/biofuel.html Biofuel archives at Infoarchive.net (searchable): http://infoarchive.net/sgroup/biofuel/ ___ Biofuel mailing list [EMAIL PROTECTED] http://wwia.org/mailman/listinfo.cgi/biofuel Biofuel at Journey to Forever: http://journeytoforever.org/biofuel.html Biofuel archives at Infoarchive.net (searchable): http://infoarchive.net/sgroup/biofuel/ ___ Biofuel mailing list [EMAIL PROTECTED] http://wwia.org/mailman/listinfo.cgi/biofuel Biofuel at Journey to Forever: http://journeytoforever.org/biofuel.html Biofuel archives at Infoarchive.net (searchable): http://infoarchive.net/sgroup/biofuel/
Re: [Biofuel] Vertical axis wind turbines Another approach to wind
automatic positioning requires controls be it a cam and a linkage or a motor and electronics. It doesn't mean an operator is on duty. Kirk --- Martin K [EMAIL PROTECTED] wrote: I don't think it has controls, I think they are positioned automatically. If this is not the case please let me know. I believe the 'controls' come down to the fact that the wind positions the flaps. There are no controls be they mechanical or electrical. -- --- Martin Klingensmith nnytech.net infoarchive.net ___ Biofuel mailing list [EMAIL PROTECTED] http://wwia.org/mailman/listinfo.cgi/biofuel Biofuel at Journey to Forever: http://journeytoforever.org/biofuel.html Biofuel archives at Infoarchive.net (searchable): http://infoarchive.net/sgroup/biofuel/
RE: [Biofuel] Vertical axis wind turbines Another approach to wind
The hours of operation aren't even close. The comparison is invalid. Incorrect as our coaches are running 16 hours a day and the loads on those turbine bears are nowhere near the loads on the drive shaft bearings behind the 200 hp motor. Chris. --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.799 / Virus Database: 543 - Release Date: 19/11/2004 ___ Biofuel mailing list [EMAIL PROTECTED] http://wwia.org/mailman/listinfo.cgi/biofuel Biofuel at Journey to Forever: http://journeytoforever.org/biofuel.html Biofuel archives at Infoarchive.net (searchable): http://infoarchive.net/sgroup/biofuel/
Re: [Biofuel] Vertical axis wind turbines Another approach to wind
From the description: Bearing little resemblance to the older prop type models, the H.O.G. is 61 feet in diameter, weighing 30,000 pounds and approximately 26 feet high. Not only huge but complex. I went to a drag design only because I have a stupidly simple idea of how to implement it. This HOG machine uses shaped blades and positions them. Complex and lots of wear points. I wish them luck as we all need cheap non polluting power but I have serious doubts about this machine. Elegance of design means simple. I would like to see a tally of wear points for this design plus fab costs. I doubt it will pencil. Kirk --- Dave Brockes [EMAIL PROTECTED] wrote: Hello everyone, I know this is a little off our usual line of topics but as the subject has been presented I thought I would throw this out along with it. I have been working with a small developer who has been doing extensive RD on a VAWT. They are currently in the middle of construction with their production model and hope to have it operational by the first week of December. I cannot refute any remarks pertaining to previous VAWT machines at this point but have a strong feeling these guys might be on to a little something here. You can go to www.newharvestenergy.com to get some basic information about them and view a short clip on their last prototype machine built last year. I can try to answer any questions you might have but for technical data the information will be limited to what they have been able to learn with other models they have built to this point. Happy Thanksgiving to all who celebrate it and enjoy this time with your families. - Original Message - From: Kirk McLoren [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Saturday, November 20, 2004 10:35 PM Subject: Re: [Biofuel] Vertical axis wind turbines Another approach to wind Not Swedish. Bohemian Celt actually. Was madly infatuated with a little Norwegian girl when we were in the 8th grade though. She told me ufda was being at the airport when your ship comes in. As to your other question -- Fatigue stress is much higher in a VAWT than a HAWT. Inescapable. To quote Hugh Piggott http://www.fieldlines.com/comments/2004/1/20/103054/698/2?mode=alone;showrate=1 I'm going to paste in my standard reply to this question. Vertical axis wind turbines are very popular in universities and with many home-builders. Attractive features include the ability to take wind from any direction and the ability to site mechanical parts at ground level. In spite of a huge amount of research, vertical axis wind turbines have failed to become widely accepted. Low speed vertical axis wind turbines of the 'Savonius' type are useful for really basic simple rugged machines with low efficiency, and low rpm. But the same amount of effort put into a horizontal axis machine will yield much greater returns. High speed Darrieus 'egg-beater' or alternatively H-rotor type vertical axis (VAWT) wind turbines are popular in university engineering departments but have never been successful in the marketplace, except briefly in California. In brief, the main problem with high speed vertical axis wind turbines is the fact that the blades suffer from reverse buffeting by the wind every single revolution. This causes severe fatigue loading which shortens the life expectancy of blades. This is usually the main reason why they fail to become commercially viable. some vertical axis urls http://www.awea.org/faq/vawt.html (good overall comparison) http://www.solwind.co.nz/ mailto:[EMAIL PROTECTED] (leo laza is/was a VAWT fanatic) http://www.windside.com/painik/menu1.htm (check out the prices) http://www.southcom.com.au/~windmill/ (savonius) http://www.iteva.org.br/tecnologias/energetica/rotor/index.asp http://www.nexwindenergy.com http://home.inreach.com/integener/ http://www.massmegawatts.com/ http://www.ecoquestintl.com/eqwindtreepop.htm http://www.ropatec.com/en http://www.aerotecture.com/ there are good books available concerning Savonius rotors made of drums. One of the best is: Savonius Rotor Construction. J.A.Kozlowski. VITA USA. 1977. 0-86619-062-7. Available from http://www.vita.org 'PicoTurbine Deluxe Windmill Plans' text is a good one. Available from http://www.picoturbine.com. At 10:28 pm +0100 14/7/02, Christopher William Turner wrote: There was hard vertical test results (from 1979!) at http://www.sandia.gov/Renewable_Energy/wind_energy/topical.htm In rough summary, a 1.5m high x 1m diameter Savonius managed a Cp of 0.22-0.25 Two bucket with 0.1d overlap is best. Use 2, vertically stacked at 90degree rotation to get even torque. A Darrius managed a Cp of 0.3-0.35. NACA0015 airfoil seems good. Solidity 0.15 to 0.2. TSR 4-6. Not self starting. I
Re: [Biofuel] Vertical axis wind turbines Another approach to wind
Kirk McLoren wrote: From the description: Bearing little resemblance to the older prop type models, the H.O.G. is 61 feet in diameter, weighing 30,000 pounds and approximately 26 feet high. Not only huge but complex. I went to a drag design only because I have a stupidly simple idea of how to implement it. This HOG machine uses shaped blades and positions them. Complex and lots of wear points. I wish them luck as we all need cheap non polluting power but I have serious doubts about this machine. Elegance of design means simple. I would like to see a tally of wear points for this design plus fab costs. I doubt it will pencil. Kirk It has many wear points but it only turns from 1 to 6 RPM. It is huge and ugly though. The blades are positioned automatically I believe. -- Martin K ___ Biofuel mailing list [EMAIL PROTECTED] http://wwia.org/mailman/listinfo.cgi/biofuel Biofuel at Journey to Forever: http://journeytoforever.org/biofuel.html Biofuel archives at Infoarchive.net (searchable): http://infoarchive.net/sgroup/biofuel/
Re: [Biofuel] Vertical axis wind turbines Another approach to wind
Kirk, Good points. I have contacts in the Wind Tunnel testing industry at a well known Research Center. If needed, you can proceed with wind tunnel testing but costs a bundle to use the facility...about $3,000 per hour!!! at the minimum for just the small wind tunnel. About $30,000 per week for a larger wind tunnel. The issue in all propollers and turbines is the wake vortices impacting the efficiency of the system. P. Wolfe --- Kirk McLoren [EMAIL PROTECTED] wrote: From the description: Bearing little resemblance to the older prop type models, the H.O.G. is 61 feet in diameter, weighing 30,000 pounds and approximately 26 feet high. Not only huge but complex. I went to a drag design only because I have a stupidly simple idea of how to implement it. This HOG machine uses shaped blades and positions them. Complex and lots of wear points. I wish them luck as we all need cheap non polluting power but I have serious doubts about this machine. Elegance of design means simple. I would like to see a tally of wear points for this design plus fab costs. I doubt it will pencil. Kirk --- Dave Brockes [EMAIL PROTECTED] wrote: Hello everyone, I know this is a little off our usual line of topics but as the subject has been presented I thought I would throw this out along with it. I have been working with a small developer who has been doing extensive RD on a VAWT. They are currently in the middle of construction with their production model and hope to have it operational by the first week of December. I cannot refute any remarks pertaining to previous VAWT machines at this point but have a strong feeling these guys might be on to a little something here. You can go to www.newharvestenergy.com to get some basic information about them and view a short clip on their last prototype machine built last year. I can try to answer any questions you might have but for technical data the information will be limited to what they have been able to learn with other models they have built to this point. Happy Thanksgiving to all who celebrate it and enjoy this time with your families. - Original Message - From: Kirk McLoren [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Saturday, November 20, 2004 10:35 PM Subject: Re: [Biofuel] Vertical axis wind turbines Another approach to wind Not Swedish. Bohemian Celt actually. Was madly infatuated with a little Norwegian girl when we were in the 8th grade though. She told me ufda was being at the airport when your ship comes in. As to your other question -- Fatigue stress is much higher in a VAWT than a HAWT. Inescapable. To quote Hugh Piggott http://www.fieldlines.com/comments/2004/1/20/103054/698/2?mode=alone;showrate=1 I'm going to paste in my standard reply to this question. Vertical axis wind turbines are very popular in universities and with many home-builders. Attractive features include the ability to take wind from any direction and the ability to site mechanical parts at ground level. In spite of a huge amount of research, vertical axis wind turbines have failed to become widely accepted. Low speed vertical axis wind turbines of the 'Savonius' type are useful for really basic simple rugged machines with low efficiency, and low rpm. But the same amount of effort put into a horizontal axis machine will yield much greater returns. High speed Darrieus 'egg-beater' or alternatively H-rotor type vertical axis (VAWT) wind turbines are popular in university engineering departments but have never been successful in the marketplace, except briefly in California. In brief, the main problem with high speed vertical axis wind turbines is the fact that the blades suffer from reverse buffeting by the wind every single revolution. This causes severe fatigue loading which shortens the life expectancy of blades. This is usually the main reason why they fail to become commercially viable. some vertical axis urls http://www.awea.org/faq/vawt.html (good overall comparison) http://www.solwind.co.nz/ mailto:[EMAIL PROTECTED] (leo laza is/was a VAWT fanatic) http://www.windside.com/painik/menu1.htm (check out the prices) http://www.southcom.com.au/~windmill/ (savonius) http://www.iteva.org.br/tecnologias/energetica/rotor/index.asp http://www.nexwindenergy.com http://home.inreach.com/integener/ http://www.massmegawatts.com/ http://www.ecoquestintl.com/eqwindtreepop.htm http://www.ropatec.com/en http://www.aerotecture.com/ there are good books available concerning Savonius rotors made of drums. One of the best is: Savonius Rotor Construction. J.A.Kozlowski. VITA USA. 1977. 0-86619-062-7. Available
RE: [Biofuel] Vertical axis wind turbines Another approach to wind
Elegance of design means simple. I would like to see a tally of wear points for this design plus fab costs. I doubt it will pencil. If the sealed grease bearings on my truck can be made to last 10 years I see no problem if it's built well enough. There is no reason these days to have short bearing life. Chris. --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.799 / Virus Database: 543 - Release Date: 19/11/2004 ___ Biofuel mailing list [EMAIL PROTECTED] http://wwia.org/mailman/listinfo.cgi/biofuel Biofuel at Journey to Forever: http://journeytoforever.org/biofuel.html Biofuel archives at Infoarchive.net (searchable): http://infoarchive.net/sgroup/biofuel/
RE: [Biofuel] Vertical axis wind turbines Another approach to wind
The hours of operation aren't even close. The comparison is invalid. Then there is the question of which bearings you refer to. Wheel bearings? Totally different application from moving the foils. The applied loads in that machine are very large. That makes the controls large which means expensive. The bottom line is mostly cost. I don't think that machine has anything new to offer in that area. It is new and novel. So what? Economics determine viability. Since it uses rigid foils I'm not sure it even has much advantage in the dead bird problem. Still not enthused. Kirk --- Chris Lloyd [EMAIL PROTECTED] wrote: Elegance of design means simple. I would like to see a tally of wear points for this design plus fab costs. I doubt it will pencil. If the sealed grease bearings on my truck can be made to last 10 years I see no problem if it's built well enough. There is no reason these days to have short bearing life. Chris. __ Do you Yahoo!? Meet the all-new My Yahoo! - Try it today! http://my.yahoo.com ___ Biofuel mailing list [EMAIL PROTECTED] http://wwia.org/mailman/listinfo.cgi/biofuel Biofuel at Journey to Forever: http://journeytoforever.org/biofuel.html Biofuel archives at Infoarchive.net (searchable): http://infoarchive.net/sgroup/biofuel/
Re: [Biofuel] Vertical axis wind turbines Another approach to wind
Kirk, There's nothing wrong with vertical-axis wind turbines (VAWTs), in principle. All turbines deal with turbulent loads more or less. The problem is with business attitudes-- companies dropped the VAWTs when they were not looking competitive, and now few people are willing to go back and take a second look. I think I know how to solve the VAWT problems when somebody is ready. Now, to jog your sense of reality-- it may be that the next move into VAWTs will be for use under-water. You know, wave and tide power. Are you Swedish? (OOPS, forgive me, I guess we're a little off-topic, aren't we! ) Ernie Rogers In a message dated 11/20/2004 11:07:48 AM Mountain Standard Time, [EMAIL PROTECTED] writes: All the VAT I know about suffered fatigue and broke due to reversal every revolution. It is a design weakness. All you can do is select materials etc to extend mtbf but it is built in. I used to be enthusiastic about them as I wanted to avoid the problems in the conventional designs. They aren't the answer either. Ufda. Kirk ___ Biofuel mailing list [EMAIL PROTECTED] http://wwia.org/mailman/listinfo.cgi/biofuel Biofuel at Journey to Forever: http://journeytoforever.org/biofuel.html Biofuel archives at Infoarchive.net (searchable): http://infoarchive.net/sgroup/biofuel/
Re: [Biofuel] Vertical axis wind turbines Another approach to wind
Not Swedish. Bohemian Celt actually. Was madly infatuated with a little Norwegian girl when we were in the 8th grade though. She told me ufda was being at the airport when your ship comes in. As to your other question -- Fatigue stress is much higher in a VAWT than a HAWT. Inescapable. To quote Hugh Piggott http://www.fieldlines.com/comments/2004/1/20/103054/698/2?mode=alone;showrate=1 I'm going to paste in my standard reply to this question. Vertical axis wind turbines are very popular in universities and with many home-builders. Attractive features include the ability to take wind from any direction and the ability to site mechanical parts at ground level. In spite of a huge amount of research, vertical axis wind turbines have failed to become widely accepted. Low speed vertical axis wind turbines of the 'Savonius' type are useful for really basic simple rugged machines with low efficiency, and low rpm. But the same amount of effort put into a horizontal axis machine will yield much greater returns. High speed Darrieus 'egg-beater' or alternatively H-rotor type vertical axis (VAWT) wind turbines are popular in university engineering departments but have never been successful in the marketplace, except briefly in California. In brief, the main problem with high speed vertical axis wind turbines is the fact that the blades suffer from reverse buffeting by the wind every single revolution. This causes severe fatigue loading which shortens the life expectancy of blades. This is usually the main reason why they fail to become commercially viable. some vertical axis urls http://www.awea.org/faq/vawt.html (good overall comparison) http://www.solwind.co.nz/ mailto:[EMAIL PROTECTED] (leo laza is/was a VAWT fanatic) http://www.windside.com/painik/menu1.htm (check out the prices) http://www.southcom.com.au/~windmill/ (savonius) http://www.iteva.org.br/tecnologias/energetica/rotor/index.asp http://www.nexwindenergy.com http://home.inreach.com/integener/ http://www.massmegawatts.com/ http://www.ecoquestintl.com/eqwindtreepop.htm http://www.ropatec.com/en http://www.aerotecture.com/ there are good books available concerning Savonius rotors made of drums. One of the best is: Savonius Rotor Construction. J.A.Kozlowski. VITA USA. 1977. 0-86619-062-7. Available from http://www.vita.org 'PicoTurbine Deluxe Windmill Plans' text is a good one. Available from http://www.picoturbine.com. At 10:28 pm +0100 14/7/02, Christopher William Turner wrote: There was hard vertical test results (from 1979!) at http://www.sandia.gov/Renewable_Energy/wind_energy/topical.htm In rough summary, a 1.5m high x 1m diameter Savonius managed a Cp of 0.22-0.25 Two bucket with 0.1d overlap is best. Use 2, vertically stacked at 90degree rotation to get even torque. A Darrius managed a Cp of 0.3-0.35. NACA0015 airfoil seems good. Solidity 0.15 to 0.2. TSR 4-6. Not self starting. I think HAWTs manage Cp of 0.48 and use much less blade material. -- Christopher William Turner, http://www.cycom.co.uk/ Hugh Piggott http://www.scoraigwind.co.uk --- [EMAIL PROTECTED] wrote: Kirk, There's nothing wrong with vertical-axis wind turbines (VAWTs), in principle. All turbines deal with turbulent loads more or less. The problem is with business attitudes-- companies dropped the VAWTs when they were not looking competitive, and now few people are willing to go back and take a second look. I think I know how to solve the VAWT problems when somebody is ready. Now, to jog your sense of reality-- it may be that the next move into VAWTs will be for use under-water. You know, wave and tide power. Are you Swedish? (OOPS, forgive me, I guess we're a little off-topic, aren't we! ) Ernie Rogers In a message dated 11/20/2004 11:07:48 AM Mountain Standard Time, [EMAIL PROTECTED] writes: All the VAT I know about suffered fatigue and broke due to reversal every revolution. It is a design weakness. All you can do is select materials etc to extend mtbf but it is built in. I used to be enthusiastic about them as I wanted to avoid the problems in the conventional designs. They aren't the answer either. Ufda. Kirk __ Do you Yahoo!? The all-new My Yahoo! - Get yours free! http://my.yahoo.com ___ Biofuel mailing list [EMAIL PROTECTED] http://wwia.org/mailman/listinfo.cgi/biofuel Biofuel at Journey to Forever: http://journeytoforever.org/biofuel.html Biofuel archives at Infoarchive.net (searchable): http://infoarchive.net/sgroup/biofuel/
Re: [Biofuel] Vertical axis wind turbines Another approach to wind
I know this is a little off our usual line of topics but as the subject has been presented I thought I would throw this out along with it. I have been working with a small developer who has been doing extensive RD on a VAWT. They are currently in the middle of construction with their production model and hope to have it operational by the first week of December. I cannot refute any remarks pertaining to previous VAWT machines at this point but have a strong feeling these guys might be on to a little something here. You can go to www.newharvestenergy.com to get some basic information about them and view a short clip on their last prototype machine built last year. I can try to answer any questions you might have but for technical data the information will be limited to what they have been able to learn with other models they have built to this point. Happy Thanksgiving to all who celebrate it and enjoy this time with your families. - Original Message - From: Kirk McLoren [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Saturday, November 20, 2004 10:35 PM Subject: Re: [Biofuel] Vertical axis wind turbines Another approach to wind Not Swedish. Bohemian Celt actually. Was madly infatuated with a little Norwegian girl when we were in the 8th grade though. She told me ufda was being at the airport when your ship comes in. As to your other question -- Fatigue stress is much higher in a VAWT than a HAWT. Inescapable. To quote Hugh Piggott http://www.fieldlines.com/comments/2004/1/20/103054/698/2?mode=alone;showrate=1 I'm going to paste in my standard reply to this question. Vertical axis wind turbines are very popular in universities and with many home-builders. Attractive features include the ability to take wind from any direction and the ability to site mechanical parts at ground level. In spite of a huge amount of research, vertical axis wind turbines have failed to become widely accepted. Low speed vertical axis wind turbines of the 'Savonius' type are useful for really basic simple rugged machines with low efficiency, and low rpm. But the same amount of effort put into a horizontal axis machine will yield much greater returns. High speed Darrieus 'egg-beater' or alternatively H-rotor type vertical axis (VAWT) wind turbines are popular in university engineering departments but have never been successful in the marketplace, except briefly in California. In brief, the main problem with high speed vertical axis wind turbines is the fact that the blades suffer from reverse buffeting by the wind every single revolution. This causes severe fatigue loading which shortens the life expectancy of blades. This is usually the main reason why they fail to become commercially viable. some vertical axis urls http://www.awea.org/faq/vawt.html (good overall comparison) http://www.solwind.co.nz/ mailto:[EMAIL PROTECTED] (leo laza is/was a VAWT fanatic) http://www.windside.com/painik/menu1.htm (check out the prices) http://www.southcom.com.au/~windmill/ (savonius) http://www.iteva.org.br/tecnologias/energetica/rotor/index.asp http://www.nexwindenergy.com http://home.inreach.com/integener/ http://www.massmegawatts.com/ http://www.ecoquestintl.com/eqwindtreepop.htm http://www.ropatec.com/en http://www.aerotecture.com/ there are good books available concerning Savonius rotors made of drums. One of the best is: Savonius Rotor Construction. J.A.Kozlowski. VITA USA. 1977. 0-86619-062-7. Available from http://www.vita.org 'PicoTurbine Deluxe Windmill Plans' text is a good one. Available from http://www.picoturbine.com. At 10:28 pm +0100 14/7/02, Christopher William Turner wrote: There was hard vertical test results (from 1979!) at http://www.sandia.gov/Renewable_Energy/wind_energy/topical.htm In rough summary, a 1.5m high x 1m diameter Savonius managed a Cp of 0.22-0.25 Two bucket with 0.1d overlap is best. Use 2, vertically stacked at 90degree rotation to get even torque. A Darrius managed a Cp of 0.3-0.35. NACA0015 airfoil seems good. Solidity 0.15 to 0.2. TSR 4-6. Not self starting. I think HAWTs manage Cp of 0.48 and use much less blade material. -- Christopher William Turner, http://www.cycom.co.uk/ Hugh Piggott http://www.scoraigwind.co.uk --- [EMAIL PROTECTED] wrote: Kirk, There's nothing wrong with vertical-axis wind turbines (VAWTs), in principle. All turbines deal with turbulent loads more or less. The problem is with business attitudes-- companies dropped the VAWTs when they were not looking competitive, and now few people are willing to go back and take a second look. I think I know how to solve the VAWT problems when somebody is ready. Now, to jog your sense of reality-- it may be that the next move into VAWTs will be for use under-water. You know, wave and tide power. Are you Swedish? (OOPS, forgive me, I guess we're a little off-topic, aren't we! ) Ernie Rogers In a message dated 11/20/2004 11:07:48 AM Mountain Standard Time, [EMAIL PROTECTED
[Biofuel] Vertical axis wind turbines Another approach to wind
another approach to wind Vertical-axis turbines may avoid the limitations of today's standard propeller-like machines. by Steven Peaceby Jun 2004 http://www.memagazine.org/backissues/jun04/features/apptowind/apptowind.html The image of modern wind turbines has finally crept into the public consciousness. At long last, the Dutch windmill and the Great Plains wind-powered water pump have been supplanted by something sleek and futuristic: a tower that is 10, 20, even 30 stories tall with a rotor comprising two or three thin blades. But the image does not fully account for the reality. Anyone not directly involved in the wind turbine industry might be forgiven for thinking that all wind turbines face into the wind, with a horizontal axis of rotation. But there is another, less familiar, type of wind turbine, with a vertical axis. It has origins going back much farther in history than the common propeller-type, horizontal-axis turbines. Horizontal-axis wind turbine technology is likely to peak in the next few years, largely because of the limitations of the blades and their effects on the machine. The power output of a wind turbine is directly related to the swept area of its blades. The larger the diameter, the more power it is capable of extracting from the wind. The larger the blades, the stronger they need to be to withstand the higher levels of centrifugal force and stresses caused by their additional size and weight. The extra mass for strength adds further to the structure's weight and so compounds the problem. Furthermore, the bending moments across the swept area of the blade can vary considerably, with a possible difference of several meters a second in wind speeds between the top and the bottom of the blade's rotation. This all adds up to a substantial increase in fatigue, not only in the blade structure, but also in the machine's hub, bearing, driveshaft, and support tower. With a 31-meter (100-foot) blade weighing around 4.5 tons and a 54-meter (177-foot) blade weighing about 13 tons, the weight of the blade for a horizontal-axis turbine is not proportional to the size and power rating of the machine. Along the Vertical Axis I believe that horizontal-axis machines will prove unable to meet the growing demand for larger, more cost-effective wind turbines÷particularly with the recent trend to build on more costly, but more productive sites offshore. We need to look back in history and concentrate on further developing the simpler vertical-axis designs. Without the same structural limitations, vertical-axis turbines can be produced much larger and so take advantage of significant economies of scale. Vertical-axis windmills are not some futuristic concept. There is evidence of their existence dating back as far as the seventh century B.C. However, all the different designs can be categorized into two basic principles÷pushed by the wind or pulled by the wind. The push principle is the oldest by far, originally consisting of two or more vertical sails or paddles that are blown around their vertical axis by the wind. A Persian vertical-axis design dating from about 200 B.C. channeled the wind with walls towards the paddles of the machine, which were then pushed around by the wind. Finnish engineer S.J. Savonius substantially updated this basic concept in 1922, when he replaced the sails with cups or half oil drums with their open sides opposing each other and fixed to a central vertical shaft. The cup in line with the wind flow catches the wind and so turns the shaft 180 degrees, bringing the opposing cup into the flow. This cup then repeats the process, causing the shaft to rotate a further 180 degrees and complete a full rotation. There have been numerous variations on the same theme, some with additional cups or drums on the same shaft and some with their cups or drums set at different angles or positions on the shaft. In recent years, this principle has undergone further significant development, noticeably by two Finnish companies, Shield Oy and Windside Production Ltd. Both of these companies produce small helical or fluted bladed machines, where the drums of the Savonius rotor have evolved into spiral-formed vanes. These machines are ideal for use on buoys, offshore platforms, buildings, signs, and posts, where small amounts of power are required. They are often used to charge battery backup systems or to supplement low-voltage photovoltaic solar panels, used to power signs, public telephones, low-voltage transmitters, and other small systems. These devices benefit from being extremely rugged, quiet, and omnidirectional. They are more efficient than the conventional Savonius machine and exert less stress on their support structures. There are ambitions to scale up these types of machines to megawatt size, but research and development funding for vertical-axis
Re: [Biofuel] Vertical axis wind turbines Another approach to wind
All the VAT I know about suffered fatigue and broke due to reversal every revolution. It is a design weakness. All you can do is select materials etc to extend mtbf but it is built in. I used to be enthusiastic about them as I wanted to avoid the problems in the conventional designs. They aren't the answer either. Ufda. Kirk --- MH [EMAIL PROTECTED] wrote: another approach to wind Vertical-axis turbines may avoid the limitations of today's standard propeller-like machines. by Steven Peaceby Jun 2004 http://www.memagazine.org/backissues/jun04/features/apptowind/apptowind.html The image of modern wind turbines has finally crept into the public consciousness. At long last, the Dutch windmill and the Great Plains wind-powered water pump have been supplanted by something sleek and futuristic: a tower that is 10, 20, even 30 stories tall with a rotor comprising two or three thin blades. But the image does not fully account for the reality. Anyone not directly involved in the wind turbine industry might be forgiven for thinking that all wind turbines face into the wind, with a horizontal axis of rotation. But there is another, less familiar, type of wind turbine, with a vertical axis. It has origins going back much farther in history than the common propeller-type, horizontal-axis turbines. __ Do you Yahoo!? Meet the all-new My Yahoo! - Try it today! http://my.yahoo.com ___ Biofuel mailing list [EMAIL PROTECTED] http://wwia.org/mailman/listinfo.cgi/biofuel Biofuel at Journey to Forever: http://journeytoforever.org/biofuel.html Biofuel archives at Infoarchive.net (searchable): http://infoarchive.net/sgroup/biofuel/
