Novel wind turbine designs

02-01-2015 3:28pm

Capt'n Midnight · 02-01-2015 6:58pm

Sir Liamalot wrote: »

Ah my favourite thread of chocolate teapots has returned. :pac:

Actually there have been recent improvements in chocolate teapots.

http://www.nestle.ie/innovation/behindthescenesatnestle/makingachocolateteapot

What we discovered was the most important questions to answer were what was the right thickness of the chocolate walls and how big should be the size of the spout and top hole. If the walls were too thin, we found that they would collapse before the tea could be brewed. If the hole was too small, the condensation would cause the walls to melt too quickly, making the drink not tea but hot chocolate...

the original from 2008 http://www.thenakedscientists.com/HTML/content/kitchenscience/exp/how-useless-is-a-chocolate-teapot/

Capt'n Midnight · 02-01-2015 7:12pm

OssianSmyth wrote: »

French wind startup to make turbines that look like trees

http://www.altenergymag.com/stories/2014/12/tree-shaped-wind-turbines-blend-into-the-scenery/875

The 36-foot-tall steel structure is perfect for urban environments, where a conventional wind turbine might not fit.

Seventy-two artificial leaves that work as micro-turbines adorn the branches and spin silently on a vertical axis. Cables and generators have been integrated into the leaves and branches in a way that puts them out of sight and sound.
...

At the moment, each tree has a power output estimated at 3.1 kW.

But how much do they cost each and what's the payback time ??

Outkast_IRE · 02-01-2015 7:16pm

Capt'n Midnight wrote: »

http://www.altenergymag.com/stories/2014/12/tree-shaped-wind-turbines-blend-into-the-scenery/875But how much do they cost each and what's the payback time ??

Also would they not be very dangerous to birds and animals ?

03-01-2015 2:15am

wrote:

At the moment, each tree has a power output estimated at 3.1 kW

:rolleyes:

Capt'n Midnight wrote: »

But how much do they cost each and what's the payback time ??

You'd be lucky if ever.

Outkast_IRE wrote: »

Also would they not be very dangerous to birds and animals ?

Nope. Only the useful ones are harmful to creatures. The ones who's blades spin faster than the wind and produce real power.

03-01-2015 6:08am

Japanese hybrid wind & tidal.
Link

It sank. ...twice...

Capt'n Midnight · 03-01-2015 12:56pm

Typical Cost breakdown of wind turbine

Items of note - Almost all the costs are the same.

Generator 3% , so rare earth shortages aren't a show stopper, the transformer and power converters cost more.

Pitch/ Yaw System - not all the novelty designs have mechanisms to handle variable speed wind or to idle in storms - and that means you need to spend a lot more making it stronger.

Development cost 2% - one advantage of dealing with a mature product and economies of scale.

Blades 16% - this is really the main one that alternatives might change, but usually at the expense of ducts or fans that cost more and have more wind loading so you have to pay more for the tower and civil works and possibly gearbox. Add development costs and insurance etc.

03-01-2015 6:11pm

Size matters with wind. Cheapest way to get a production increase is more swept area and height into clean non-turbulent air. So while these ducted turbines may produce more than a comparative blade diameter of a traditional HAWT. It's a lot more economical build a simple design higher and put bigger blades on it.

Capt'n Midnight · 03-01-2015 9:27pm

Sir Liamalot wrote: »

Size matters with wind. Cheapest way to get a production increase is more swept area and height into clean non-turbulent air. So while these ducted turbines may produce more than a comparative blade diameter of a traditional HAWT. It's a lot more economical build a simple design higher and put bigger blades on it.

Ducts, stators, increasing the number of blades, using a second set of blades rotating the other way will all increase efficiency at which you can power you can extract from a given diameter.

But Bentz' Law means you can't ever extract more than 16/27ths of the wind energy over the area you capture.

Making longer thinner blades will increase the diameter you can extract power from.

OK there are lots of other effects like fans having higher torque , but if you consider optimising for a particular wind speed then to bridge the gap between a good 80% efficient three blade wind turbine and a novel design that reached 100% of theoretical efficiency you'd only have to make the three blades 11% longer.

Two blades would of course be even more efficient and several single bladed designs have been used but three blades seems to be the best compromise given that more vibration means you need to spend more on the tower. Though offshore means you need to stand up to waves so perhaps we may see two blades in use there some time.

04-01-2015 3:53am

Siemens are installing whole rotors these days, rather than a blade at a time.

04-01-2015 8:30am

Capt'n Midnight wrote: »

we may see two blades in use there some time.

Ta-da!

sycamore-seed-shaped-vertical-axis-wind-turbine-1_bRwjs_11446.jpg

Link

Capt'n Midnight wrote: »

...how much do they cost each and what's the payback time ??

Here's a good one for a vertical darrieus.
......no idea how they managed to spend £48K on that lemon. A Proven WT6000 / Kingspan KW6 is £30K with groundworks.

recedite · 04-01-2015 1:11pm

Sir Liamalot wrote: »

Sail, no Betz Limit

Is that true though, no Betz limit for a sail? I'm not sure "a sail" and "a blade" are all that different to each other in principle?

Sir Liamalot wrote: »

Link

"....the other end is held aloft by a balloon"
What could possibly go wrong!

Still, it looks pretty.

04-01-2015 6:21pm

recedite wrote: »

Is that true though, no Betz limit for a sail? I'm not sure "a sail" and "a blade" are all that different to each other in principle?

Sails are subject to the Betz limit. That particular turbine I don't know. Blades rely heavily on the low pressure in their wake to create lift. Tbh most of these designs are vastly over-rated and unsubstantiated.
I wouldn't touch a turbine that hasn't published a power curve with a cut-in windspeed ~3.5m/s and producing decent power @ > 5m/s.
The whole industry is infected with unrealistic claims. The power ratings of turbines are for max. RPM, a lot of the Chinese derive this from hurricane strength wind.
I generally find TED a reliable source so could be worth investigating. That it's a linear based kinetic generator and not a rotary or towing force may have a part to play. It may even rely on stalling the wind to reset the spring.
I'd happily put a Hugh Piggott Design side by side any of these and expect his rugged wooden blades on a car wheel hub turning a hand wound alternator to out-perform most the aforementioned of a comparable scale when it matters and furl when it's already probably finished charging.

recedite wrote: »

Still, it looks pretty.

That hill in the background looks a bit Photoshopped to me.

recedite · 04-01-2015 11:26pm

Sir Liamalot wrote: »

I generally find TED a reliable source..

Thats what I was thinking; surely he would not be able to spout some marketing BS on a Ted talk and then receive a round of applause. But then again... He mentioned several times that it was derived from a sail, not that it acted as one. As it keeps jumping from side to side, it must be stalling the wind in position A, then moving to position B. Hence "in theory" it may not be subject to the Betz limit, but the back and forth movement must be creating worse inefficiencies. The turbulence and the violent battering of the structure would probably be terrible in a large scale version.

05-01-2015 5:06am

Here's a closer look at the prototype.

saphonzeroblade.jpg.650x0_q85_crop-smart.jpg

2.3 times more efficient than a rotor. Looks like it's pumping rams from various offsets of the dish...probably riding on a ball joint.

Saphon wrote:

Instead of blades rotating, a sail-shaped body moves back and forth with the wind current, converting its kinetic energy into mechanical energy to move pistons. The movement of the pistons creates hydraulic pressure that can either be stored in a hydraulic accumulator or converted to electricity through a hydraulic motor and generator. The aerodynamic shape means drag force becomes the driving force of the system while the lift force becomes almost nil.

recedite · 05-01-2015 12:06pm

It seems more like a fluttering parachute than a sail. The stresses on the structural frame of a large scale version would probably be enormous.

Jim Martin · 05-01-2015 12:17pm

Million pound 80 Metre Wind Turbine collapses in County Tyrone!

http://www.demotix.com/news/6579490/million-pound-80-metre-wind-turbine-collapses-county-tyrone#media-6579454

05-01-2015 5:10pm

Looks like the market crashed too. :pac:
Only worth £500, 000 here.
£2, 000, 000 here.

Better result than Fukushima anyways.

05-01-2015 9:06pm

Debunked

But wait there's more! Now the hybrid chocy-pot...complete with ground facing PV panels...and a graph!!

05-01-2015 9:26pm

images?q=tbn:ANd9GcSK24mq3P1W5toaqLw56sSETnRmjrvlUC8SL0ATYMcyfQB_4rpy

Gone Bust

All torque and no electrons.

The Pitch: Apples vs Oranges

The Truth

05-01-2015 9:38pm

Link

Oh dear, oh dear google trackers are bombarding me with chocy-pots now :pac:

05-01-2015 10:03pm

Here we are:
Sheerwind Invelox; Mythbusted

Clean Technica wrote:

It makes the extraordinary claim of generating six times the energy of a comparable wind turbine, but in fact is likely generating about eighteen times less for perhaps ten times the material.

05-01-2015 10:14pm

Anyone recognise that turbine at the funnel mouth?

05-01-2015 11:05pm

519f98feb3fc4b39ee00002d_straw-scraper-belatchew-arkitektur_belatchew_arkitekter_strawscraper-1-528x388.jpg

Link

05-01-2015 11:10pm

This exposé says it all really.

Saphon patent here for those interested.

Questionable how long the rams can sustain life atop a mast.

recedite wrote: »

The stresses on the structural frame of a large scale version would probably be enormous.

There's probably a limit on how upscalable the design concept is alright.

recedite · 06-01-2015 9:15pm

A rooftop mounted Sheerwind invelox might be useful for pumping fresh air into a building (in hot countries). That's about it, though.

Thargor · 06-01-2015 10:16pm

Sir Liamalot wrote: »

Questionable how long the rams can sustain life atop a mast.

First thing I thought aswell, would the lifespan without maintenance be measured in weeks even?

06-01-2015 10:26pm

Good thread here on solar trackers. He's having troubles with water ingress to the rams after a year.

06-01-2015 10:28pm

recedite wrote: »

A rooftop mounted Sheerwind invelox might be useful for pumping fresh air into a building (in hot countries). That's about it, though.

Better off with solar PV and air con. I reckon.

[Edit]: It's not a real product by the way just a scam to generate revenue from gullible investors.

Capt'n Midnight · 06-01-2015 11:13pm

recedite wrote: »

A rooftop mounted Sheerwind invelox might be useful for pumping fresh air into a building (in hot countries). That's about it, though.

Passive windcatchers have been in use for over three thousand years. http://en.wikipedia.org/wiki/Windcatcher

Novel wind turbine designs

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