What a surprise...
B&Q takes wind turbines off shelves Turbine range withdrawn from sale after
recent survey reveals they don't work as effectively as first thought http://www.diyweek.net/news/news.asp?id=11999 -- Dave - The Medway Handyman www.medwayhandyman.co.uk |
What a surprise...
In message , The Medway
Handyman wrote B&Q takes wind turbines off shelves Turbine range withdrawn from sale after recent survey reveals they don't work as effectively as first thought http://www.diyweek.net/news/news.asp?id=11999 There were many discussions about this form of eco-bollox at the time that B&Q first started stocking the wind turbines. Studies had already been published that concluded that in the majority of urban environments that the energy produced to the £1k investment would be negligible. -- Alan news2006 {at} amac {dot} f2s {dot} com |
What a surprise...
On Thu, 12 Feb 2009 18:38:09 GMT, "The Medway Handyman"
wrote: B&Q takes wind turbines off shelves Turbine range withdrawn from sale after recent survey reveals they don't work as effectively as first thought http://www.diyweek.net/news/news.asp?id=11999 Hmm - I wonder if they'll now give refunds to purchasers on the grounds of unfitness for purpose. Or perhaps misleading advertising. -- Frank Erskine |
What a surprise...
Frank Erskine wrote:
On Thu, 12 Feb 2009 18:38:09 GMT, "The Medway Handyman" wrote: B&Q takes wind turbines off shelves Turbine range withdrawn from sale after recent survey reveals they don't work as effectively as first thought http://www.diyweek.net/news/news.asp?id=11999 Hmm - I wonder if they'll now give refunds to purchasers on the grounds of unfitness for purpose. Or perhaps misleading advertising. There were some purchasers? -- Rod Hypothyroidism is a seriously debilitating condition with an insidious onset. Although common it frequently goes undiagnosed. www.thyromind.info www.thyroiduk.org www.altsupportthyroid.org |
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In article ,
Frank Erskine writes: On Thu, 12 Feb 2009 18:38:09 GMT, "The Medway Handyman" wrote: B&Q takes wind turbines off shelves Turbine range withdrawn from sale after recent survey reveals they don't work as effectively as first thought http://www.diyweek.net/news/news.asp?id=11999 Hmm - I wonder if they'll now give refunds to purchasers on the grounds of unfitness for purpose. Or perhaps misleading advertising. It sort of implies they will, and says they're even proactively contacting the purchasers of them to let them know. I wonder if they're getting the money back from their suppliers? -- Andrew Gabriel [email address is not usable -- followup in the newsgroup] |
What a surprise...
"The Medway Handyman" wrote in message m... B&Q takes wind turbines off shelves Turbine range withdrawn from sale after recent survey reveals they don't work as effectively as first thought http://www.diyweek.net/news/news.asp?id=11999 This subject has been on my mind for the past 2 days. All wind turbines seem to be blades mounted vertically on a horizontal axle/axis. These can only be 100% efficient if the wind blows directly onto the face of the blades. If instead of blades they had the things you see on some wid speed measurement devices that have 3 or more cup shaped receptacles on horizontal bars fixed to a vertical axis. The wind can hit these assemblies at any angle it chooses with no difference to the efficiency of the 'machine'. I can only conclude that the prevalance of bladed wind turbines means there is a basic weakness of the wind-vane method.eg transmission of energy or torque or something like that. Anyone got any ideas on this? Arthur |
What a surprise...
"geoff" wrote in message ... In message , Frank Erskine writes On Thu, 12 Feb 2009 18:38:09 GMT, "The Medway Handyman" wrote: B&Q takes wind turbines off shelves Turbine range withdrawn from sale after recent survey reveals they don't work as effectively as first thought http://www.diyweek.net/news/news.asp?id=11999 Hmm - I wonder if they'll now give refunds to purchasers on the grounds of unfitness for purpose. Or perhaps misleading advertising. I'm waiting for them to ban dolphin showers as being unfit for porpoise -- geoff {Writes word 'geoff' on piece of paper and discovers has inadvertantly carved it into laminated desk surface} Arthur |
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In message , Frank Erskine
writes On Thu, 12 Feb 2009 18:38:09 GMT, "The Medway Handyman" wrote: B&Q takes wind turbines off shelves Turbine range withdrawn from sale after recent survey reveals they don't work as effectively as first thought http://www.diyweek.net/news/news.asp?id=11999 Hmm - I wonder if they'll now give refunds to purchasers on the grounds of unfitness for purpose. Or perhaps misleading advertising. I'm waiting for them to ban dolphin showers as being unfit for porpoise -- geoff |
What a surprise...
Arthur2 wrote:
"The Medway Handyman" wrote in message m... B&Q takes wind turbines off shelves Turbine range withdrawn from sale after recent survey reveals they don't work as effectively as first thought http://www.diyweek.net/news/news.asp?id=11999 This subject has been on my mind for the past 2 days. All wind turbines seem to be blades mounted vertically on a horizontal axle/axis. These can only be 100% efficient if the wind blows directly onto the face of the blades. That is why these things have a big tail fin and a turbine body that is free to rotate - they should always face the wind if there is a nice steady flow. Needless to say in an urban environment with turbulent flow they can't ever really face the wind since it gusts from all over the place. If instead of blades they had the things you see on some wid speed measurement devices Anemometer? that have 3 or more cup shaped receptacles on horizontal bars fixed to a vertical axis. The wind can hit these assemblies at any angle it chooses with no difference to the efficiency of the 'machine'. That is what the tail does really... http://en.wikipedia.org/wiki/Anemometer -- Cheers, John. /================================================== ===============\ | Internode Ltd - http://www.internode.co.uk | |-----------------------------------------------------------------| | John Rumm - john(at)internode(dot)co(dot)uk | \================================================= ================/ |
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On Thu, 12 Feb 2009 21:51:03 +0000, Arthur2 wrote:
If instead of blades they had the things you see on some wid speed measurement devices that have 3 or more cup shaped receptacles on horizontal bars fixed to a vertical axis. The wind can hit these assemblies at any angle it chooses with no difference to the efficiency of the 'machine'. I suspect it's a bit harder to 'feather' those sorts of designs so they don't self-destruct during really high winds. Other than that though, not sure... Related note: aren't the "egg beater" vertical turbines supposed to be more efficient than horizontal-axis ones, and will also (like the anemometer) work happily with wind blowing from any direction? |
What a surprise...
On 12 Feb, 21:51, "Arthur2" wrote:
All wind turbines seem to be blades mounted vertically on a horizontal axle/axis. These can only be 100% efficient if the wind blows directly onto the face of the blades. That's why they can be trimmed into the wind Or indeed out of it, as one way to survive over-strong winds. Vertical axis machines have much lower efficiencies in comparision. They're getting better, and in gusty, crowded urban settings they might even have the advantage. |
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"Andy Dingley" wrote in message ... On 12 Feb, 21:51, "Arthur2" wrote: All wind turbines seem to be blades mounted vertically on a horizontal axle/axis. These can only be 100% efficient if the wind blows directly onto the face of the blades. That's why they can be trimmed into the wind Or indeed out of it, as one way to survive over-strong winds. Vertical axis machines have much lower efficiencies in comparision. They're getting better, and in gusty, crowded urban settings they might even have the advantage. Also I think the bladed turbines are more difficult to design mechanically and maintain. If the Anemometer had several sets of 'cups' of differing sizes with I dunno...a sophisticated gearing system that demesh cup sets if the wind is too strong and optimise for starting up after a wind drop. Arthur |
What a surprise...
On Feb 13, 8:35*am, "Arthur2" wrote:
"Andy Dingley" wrote in message ... On 12 Feb, 21:51, "Arthur2" wrote: All wind turbines seem to be blades mounted vertically on a horizontal axle/axis. These can only be 100% efficient if the wind blows directly onto the face of the blades. That's why they can be trimmed into the wind Or indeed out of it, as one way to survive over-strong winds. Vertical axis machines have much lower efficiencies in comparision. They're getting better, and in gusty, crowded urban settings they might even have the advantage. Also I think the bladed turbines are more difficult to design mechanically and maintain. If the Anemometer had several sets of 'cups' of differing sizes with I dunno...a sophisticated gearing system that demesh cup sets if the wind is too strong and optimise for starting up after a wind drop. Arthur Isn't part of the problem that the "cups" have to be driven in reverse through the air-flow though? So when facing the wind, the cup catches the air and is driven backwards, but the cup on the exact reverse of the pole is actually having to go forwards through the wind? Matt |
What a surprise...
On 13 Feb, 09:09, wrote:
On Feb 13, 8:35*am, "Arthur2" wrote: "Andy Dingley" wrote in message .... On 12 Feb, 21:51, "Arthur2" wrote: All wind turbines seem to be blades mounted vertically on a horizontal axle/axis. These can only be 100% efficient if the wind blows directly onto the face of the blades. That's why they can be trimmed into the wind Or indeed out of it, as one way to survive over-strong winds. Vertical axis machines have much lower efficiencies in comparision. They're getting better, and in gusty, crowded urban settings they might even have the advantage. Also I think the bladed turbines are more difficult to design mechanically and maintain. If the Anemometer had several sets of 'cups' of differing sizes with I dunno...a sophisticated gearing system that demesh cup sets if the wind is too strong and optimise for starting up after a wind drop. Arthur Isn't part of the problem that the "cups" have to be driven in reverse through the air-flow though? *So when facing the wind, the cup catches the air and is driven backwards, but the cup on the exact reverse of the pole is actually having to go forwards through the wind? Matt If the cup was a cone or bugle shape the resistance would be reduced significantly I would assume. Arthur |
What a surprise...
wrote in message ... Isn't part of the problem that the "cups" have to be driven in reverse through the air-flow though? So when facing the wind, the cup catches the air and is driven backwards, but the cup on the exact reverse of the pole is actually having to go forwards through the wind? And it has to do so faster than the one going with the wind. Not ideal for generating power rather than counting revs. |
What a surprise...
We were somewhere around Barstow, on the edge of the desert, when the
drugs began to take hold. I remember geoff saying something like: Hmm - I wonder if they'll now give refunds to purchasers on the grounds of unfitness for purpose. Or perhaps misleading advertising. I'm waiting for them to ban dolphin showers as being unfit for porpoise Is this your coat? The one with 'Tarbuck' embroidered on the breast pocket? |
What a surprise...
This subject has been on my mind for the past 2 days. All wind turbines seem to be blades mounted vertically on a horizontal axle/axis. These can only be 100% efficient if the wind blows directly onto the face of the blades. Can never be 100% efficient. or else you would be left with still air behind the blades, thus blocking the incoming. Usually significantly less the 50% efficeincy to allow the air after the blades to have some energy left to carry it away. |
What a surprise...
Ian_m wrote:
This subject has been on my mind for the past 2 days. All wind turbines seem to be blades mounted vertically on a horizontal axle/axis. These can only be 100% efficient if the wind blows directly onto the face of the blades. Can never be 100% efficient. or else you would be left with still air behind the blades, thus blocking the incoming. Usually significantly less the 50% efficeincy to allow the air after the blades to have some energy left to carry it away. around 1-5% actually. If you take the actual kinetic energy of teh whole wind mass up[ to the blade tip hight over the windfarm area. If it were 50% the windmills downwind would stop turning. |
What a surprise...
In message , Grimly
Curmudgeon writes We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember geoff saying something like: Hmm - I wonder if they'll now give refunds to purchasers on the grounds of unfitness for purpose. Or perhaps misleading advertising. I'm waiting for them to ban dolphin showers as being unfit for porpoise Is this your coat? The one with 'Tarbuck' embroidered on the breast pocket? my coat has left without me ... -- geoff |
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Jules wrote:
On Thu, 12 Feb 2009 21:51:03 +0000, Arthur2 wrote: If instead of blades they had the things you see on some wid speed measurement devices that have 3 or more cup shaped receptacles on horizontal bars fixed to a vertical axis. The wind can hit these assemblies at any angle it chooses with no difference to the efficiency of the 'machine'. I suspect it's a bit harder to 'feather' those sorts of designs so they don't self-destruct during really high winds. Other than that though, not sure... Related note: aren't the "egg beater" vertical turbines supposed to be more efficient than horizontal-axis ones, and will also (like the anemometer) work happily with wind blowing from any direction? I don't believe the Darius rotor is more efficient, but the multi-directionality is an advantage. Another attraction is that in principle it could be cheaper to build. Numerous attempts have been made to design a practical Darius rotor, but none has taken off (so to speak). One major problem with the design is that the blades experience oscillating loads as they rotate - on half the cycle to force is towards the axis, on the other half it is away from it. This tends to cause fatigue failures in the blades. (I speak with feeling: I am still a shareholder in a more-or-less defunct company that was started with the aim of developing a commercially viable Darius rotor.) |
What a surprise...
Arthur2 wrote:
"The Medway Handyman" wrote in message m... B&Q takes wind turbines off shelves Turbine range withdrawn from sale after recent survey reveals they don't work as effectively as first thought http://www.diyweek.net/news/news.asp?id=11999 This subject has been on my mind for the past 2 days. All wind turbines seem to be blades mounted vertically on a horizontal axle/axis. These can only be 100% efficient if the wind blows directly onto the face of the blades. If instead of blades they had the things you see on some wid speed measurement devices that have 3 or more cup shaped receptacles on horizontal bars fixed to a vertical axis. The wind can hit these assemblies at any angle it chooses with no difference to the efficiency of the 'machine'. I can only conclude that the prevalance of bladed wind turbines means there is a basic weakness of the wind-vane method.eg transmission of energy or torque or something like that. Anyone got any ideas on this? Arthur Hopeless efficiency. Extracting energy from the wind requires use of airfoils and very careful attention to aerodynamics. |
What a surprise...
On Fri, 13 Feb 2009 08:44:12 GMT, The Medway Handyman wrote:
One phone in caller made a point that possibly a better way to save energy would be to shut the store an hour earlier . Now that is a good point. But this is about greenwash, not saving enegy. Or even energy. B-) I doubt 6kW (which is no doubt the maximum rated output) would be enough to keep half the lights on in a Tesco. They'd save *far* *Far* more energy by not having the so called 24hrs shopping. I say "so called" 'cause the one time I did want to shop late at night I went to one of these 24hr Tescos and it was shut... -- Cheers Dave. |
What a surprise...
Dave Liquorice wrote:
On Fri, 13 Feb 2009 08:44:12 GMT, The Medway Handyman wrote: One phone in caller made a point that possibly a better way to save energy would be to shut the store an hour earlier . Now that is a good point. But this is about greenwash, not saving enegy. Or even energy. B-) I doubt 6kW (which is no doubt the maximum rated output) would be enough to keep half the lights on in a Tesco. They'd save *far* *Far* more energy by not having the so called 24hrs shopping. I say "so called" 'cause the one time I did want to shop late at night I went to one of these 24hr Tescos and it was shut... They would still have the lights on for the shelf stackers though... -- Cheers, John. /================================================== ===============\ | Internode Ltd - http://www.internode.co.uk | |-----------------------------------------------------------------| | John Rumm - john(at)internode(dot)co(dot)uk | \================================================= ================/ |
What a surprise...
On Sat, 14 Feb 2009 22:18:10 +0000, John Rumm wrote:
They would still have the lights on for the shelf stackers though... I doubt it takes all night to restack the shelves, it appears to be a non-stop process when the store is open. Shelf stackers don't need the lighting level that is there for the customers either, say 75% would still be ample. I can't imagine that any of these 24hr stores get many customers past midnight to say 0600, probably depends on location though but that comes down to opening when there are customers about, like early or late to fit with shift changes at a large local employer or nearby market. -- Cheers Dave. |
What a surprise...
Dave Liquorice wrote:
I can't imagine that any of these 24hr stores get many customers past midnight to say 0600 I used to not infrequently end up in Tescos in Canley about the middle of that time bracket. Granted, its not going to be as busy as 11 o'clock on a Saturday morning, but I certainly wasn't shopping alone. The Tescos near my parents was originally 24-hours when it opened, but went to "normal" opening hours after a while due to lack of late-night custom (which doesn't surprise me where my parents live). So they don't keep them open on some sort of principle - those that open 24-hours do so because it's economically worth it. Pete |
What a surprise...
On Mon, 16 Feb 2009 00:51:30 +0000, Pete Verdon wrote:
Dave Liquorice wrote: I can't imagine that any of these 24hr stores get many customers past midnight to say 0600 I used to not infrequently end up in Tescos in Canley about the middle of that time bracket. Granted, its not going to be as busy as 11 o'clock on a Saturday morning, but I certainly wasn't shopping alone. Some 24 hour supermarkets in Germany (I think?) had 'singles nights' where you could shop for food and friends at the same time... |
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