A brave new wind

PDD

Turbines, Turbines everywhere! Everything from LED streetlamps that power themselves to advertising :-)

http://www.treehugger.com/files/2006/01/come_the_quiet_1.php

Whisper quiet so very few objections and less of an eye sore than propellor wind turbines. Plus ultra efficient new technology coming online such as:

http://www.treehugger.com/files/2005/11/ultra-effective.php

http://www.treehugger.com/files/2005/11/windside_vertic.php

Interesting

GreenDoor

If every house stuck a mini turbine on the chimbley instead of an arial it would do wonders.

I also think off shore wind farms are the best way to go. I like the idea os generating wind and wave power and not being visually bad.

air

Unfortunately this is mainly hype. Rooftop wind turbines are not successful because the airflow at low altitudes in urban areas is too turbulent due to all the obstructions etc. This causes low output, vibration and short life in any wind turbines. There are also structural issues involved in erecting a wind mill on a building, attaching one to a chimney would certainly be an efficient way to remove it.
The machine in the link is a vertical access machine also, they are not as efficient as horizontal access machines - why do you think all large wind farms use horizontal access turbines?

Solar PV panels are more suited to urban environments.

PDD

Nice one Air lets throw the baby out with the bath-water shall we? I would think that the company producing these would have factored all this in when designing the product not to mention the British Saftey Standards that they would be required to adhere to.

Besides there are many many new technologies coming on stream that are suitable for an urban environment:

http://www.treehugger.com/files/2006/04/turby_a_wind_tu.php
http://www.aerotecture.com/ - no runaway, no vibration

As for efficiencies they only come with the matruation of a technology and lets face it generation of electricity from wind with a drive for efficiencies and cost effectiveness is only recent. I mean that in a long term timescale for a technology - for example cars. The combustion engine is still based on the same basic principles it was designed around 100 years ago but I dont think a model T would compare to many modern day cars be they a standard production car or one focused on efficiency like the VW Lupo. Over the next 25 years new technologies and innovative technologies will see a massive jump in terms of efficiency that can be achieved for wind turbines for example magnetic leviation technology:

http://www.treehugger.com/files/2006/07/china_unveils_w.php

Greendoor if you like off-shore windfarms then you will love these:

http://www.treehugger.com/files/2005/11/norways_hydro_d.php

The only way things will change is when people stop accepting the same old pesimistic crap of that will never work - here's an idea lets make it ****ing work. If mankind has managed to build a nuclear bomb I think we can overcome the challenges of "turbulent air".

As a side note for the amount of money that Britain is willing to spend on a single brand new nuclear power station it could bring economic and political stability to mot of North Africa. Think people - Think BIG!

http://www.trecers.net/trec.html

boomshackala

air wrote:

The machine in the link is a vertical access machine also, they are not as efficient as horizontal access machines - why do you think all large wind farms use horizontal access turbines?

air wrote:

Au contraire mon ami. The main selling point of this innovation is the efficiency at >40% as opposed to existing horizontal axis wind turbines at <40% efficiency.

Other advantages include;
-They do not have to be turned off in high wind
-Larger horizontal axis turbines are expensive to produce as the blades extend and compress as they rotate due to their sheer size - requiring expensive materials.

These are still in development, which is why they are not currently used in commercial wind farms, but the bottom line is quieter, quicker payback wind turbines down the line..

PDD

Cheers Boom, unfortunately I dont have an engineering background to be able to full interpret all the data surrounding the technology and to investigate the validity of claims such as >40% efficiency etc. As boom said an immature technolgy thats due to make great strides.

Do ye see what happens when ye think outside the box?

air

Sorry lads, you're getting carried away with hype.
The efficiency of modern horizontal axis machines is so great that they are now coming within a few percent of extracting the maximum possible energy per unit of swept area. There simply isnt much more room for improvement, the design is pretty excellent as it is and has been refined for well over one hundred years - if thats how you want to measure the maturity of a particular technology.

What does the Maglev generator achieve? Does it use magnetic levitation to reduce bearing friction?
To be honest it looks like a total hoax to me. The article talks about harvesting the energy in low speed winds. The problem here is that there is very little energy IN low speed winds to extract in the first place. The energy passing through a given unit of swept area is directly proportional to the cube of the windspeed.
That treehugger BS article on the 'maglev' turbine makes reference to wind speeds of 1.5m/s. I'll leave it as an exercise for the reader to compare the potential energy of a unit of swept area at that wind speed versus Irelands average of approx 7m/s - hint its about a factor of 100 times less.
That alone should give you a good indication as to the quality of information in that article.

When someone can give a link to solid facts and figures from independent sources on the viability of urban wind turbines - or showing any real benefits for VAWTs for that matter, I will take some notice. Until then I will keep listening to the world leaders in the field like Hugh Pigott when they say that urban wind is an urban myth.

Takeshi_Kovacs

does sound a bit dodgy all right...


anyways, sidetracking a bit, but hows your home built turbine going, air?

lostexpectation

air wrote:

Sorry lads, you're getting carried away with hype.
The efficiency of modern horizontal axis machines is so great that they are now coming within a few percent of extracting the maximum possible energy per unit of swept area. There simply isnt much more room for improvement, the design is pretty excellent as it is and has been refined for well over one hundred years - if thats how you want to measure the maturity of a particular technology.
When someone can give a link to solid facts and figures from independent sources on the viability of urban wind turbines - or showing any real benefits for VAWTs for that matter, I will take some notice. Until then I will keep listening to the world leaders in the field like Hugh Pigott when they say that urban wind is an urban myth.

so a combination of vert/hort fan turbine isn't a solution ot turbelent air electricity generation?

boomshackala

I was referring to an article I read in the econimist about 2 months ago...They discussed the development of vertical axis turbines as I outlined above, being deveolped for wind farms....they did'nt make any reference to urban wind turbines as described in the tree hugger website afaik

air

Look, on the urban wind scene I'm no aerodynamicisist but the way I think of it is this.
The ideal scenario for a full scale normal wind turbine is a site that provides a clean consistent air flow. This makes sense to me as a turbine makes power when it faces directly into the wind. When all the wind is coming from the same direction, the full surface area of the turbine is being used effectively to provide power. However in an urban environment, turbulence is going to mean that the wind is coming from many different directions if you will. This means that the effectiveness of the turbine is going to be reduced greatly.

If you're trying to quantify how much that reduction in production is, then I cant give any hard facts - it would be very much site specific. However if you're trying to weigh it up, bear in mind that the guidelines for erecting a normal turbine usually say to site the turbine at a horizontal distance of at least 10x the turbine's hub height from any obstacles.

In any case I think that bigger issues regarding turbulence in urban environments is the strucutral problems such installations cause for their mountings and the maintenance requirements of the turbine.
For a normal turbine sited in clean air, the turbine (if operating correctly) only yaws when the direction of the wind changes. It yaws so infrequently in fact that slip rings are normally not necessary and it is usually recommended to just leave the cables loose and unplug and replug it every year or so (its rare for the wind direction to do repetitive 360 degree shifts )
In an urban environment, turbulence can potentially lead to the apparent wind direction changing at a very high frequency as gusts pass by the turbine. This reportedly leads to verh high wear and tear on the turbine as well as severe stresses on the mounting structure.

Thats about all I have to say on urban wind, I'm no expert in the field and the above is simply my deductions based on applying what I've read from people who do have experience in the field as well as a bit of simple logic.

Takeshi - The home built turbine is pretty much finished at this stage, however I cant claim too much credit for it. My friend did all the work and my role was mainly that of a 'technical advisor'
We did cop out a bit in that we purchased moulded blades for it as neither of us had the requisite tools for carving them from wood and we were getting impatient.
Our current plan is to use a twin cylinder lister generator driving a 12KW 3 phase generator to run my friends house / farm etc. The plan is to run it on waste motor oil and waste vegetable oil. The generator will be during the day time to meet peak loads and provide hot water and home heating through exhaust heat recovery. It will also run a battery charger to ensure that the bank is fully charged when its shut off. The wind generator will then keep the bank topped up overnight.
Anyway I could go on but I'll probably start a seperate thread detailing the whole affair when we've a bit more done.
Just a pps, not to put people off wind, the 2.4m turbine we have built would probably produce enough energy to keep an energy efficient house going on its own 95% of the time, its just that my friend's requirements are very high so we're just making use of the turbine within that setup to allow the generator be shut off and still not be without power.

ODS

That treehugger site is a good one - hadnt seen it before. Nice one OP