[jhowelb]

Having worked for Hall Machine Shop during the down turn in the oil industry after the "Carter inspired" energy crunch, we turned from oil recovery equipment to wind generators in an effort to survive giving me a bit of personal insight regarding the nature of wind machines.

Most catastrophic failures of these machines will be related to brakes in one way or another. Usually it's a "runaway" causing it to simply beat itself to death due to distortion caused by the extreme centrifugal and high wind forces.

Either way it is not healthy to be in the vicinity when one runs wild!

[dynosor]

Something on topic for once.

http://english.pravda.ru/print/scien...arth_ice_age-0

Add to that http://news.yahoo.com/s/ap/20090114/...e_us/snowstorm

[handlewanker]

About that Danish wind turbine going West, how did they know it was going to "evaporate", seeing as how it was filmed a few minutes before it took off?

It almost seems from the way ALL the blades suddenly disintergrated at once that a rocket was fired at it.

Having known that it was going to go "off line" permanently, and bearing in mind the cost of making and erecting the thing you'd think they would have shut it down before hand.

I don't suppose the blades have a built in "feathering" system to prevent over revving when the wind gets up.

If I was designing one of these things, and bearing in mind the cost involved when they fail, I'd have to have some kind of fail safe system that would retract the blades or just turn them completely so that they didn't turn when the wind was too strong.

I don't suppose those old Dutch windmills have the same problem, but what do the Dutch know seeing as how they were built almost 200 years ago mostly from stone and wood, and some of them are still running today.

I wonder if anyone told the Dutch that wind power was a lot of hooey and not worth the effort and cost in building them, given that most of the wind just went through the blades anyway.

Nobody I guess, and as oil hadn't been invented then, it was use whatever was practical.

I guess that the windmill has come full circle, LOL. Waterwheels next, then wood burning steam engines.

I just hope there'll be enough of the old time engineers to fix the damm things, provided they aren't too high tech and too costly to be unfixable, like computers, CD players, Microwave ovens, digital cameras and mobile phones, to name but a few of the gadgets that soak up the wealth of the nation and are dumped within such a short time frame before the paint is even dry on some of them.
Ian.

[martinw]

Dear all

Danish wind turbine,

The word I heard is the the over-speed limiter failed. It was probably a mechanical failure to furl the blades or orient it out of the wind. I can't believe that the ultimate safety feature was electical or electronic.... still you never know, it might have been designed by Microsoft......

BTW, Ian, there are plenty of other clips on youtube showing worried Danes discussing the situation before their van at the base of the tower took a near hit.

Geof, sure the blades went up and came down a bit later. They were probably made of GRP which is not entirely heavy, and given their destruction by the solid lower part of the tower, my guess is that their embodied energy was not that great, even in extremis. Ooops, tin hat time, but must go to bed.

Best wishes,
Martin

[der_fisherman]

Here are a few answers for you:-

1)It almost seems from the way ALL the blades suddenly disintegrated at once that a rocket was fired at it.
a)The weight of just part of one blade (let alone a whole blade!) will so unbalance the rest at the revs in question (probably many tons of moment!) that it is not surprising that it simply instantly flies apart...

2)Having known that it was going to go "off line" permanently, and bearing in mind the cost of making and erecting the thing you'd think they would have shut it down before hand.
a) I think that was the problem, its mechanical/electrical shut down system has failed.....

3)I don't suppose the blades have a built in "feathering" system to prevent over revving when the wind gets up.
a) I am sure it did, but it has simply failed......

4)If I was designing one of these things, and bearing in mind the cost involved when they fail, I'd have to have some kind of fail safe system that would retract the blades or just turn them completely so that they didn't turn when the wind was too strong.
a) As all designers of large (and small) windmills do.....maybe not well enough though in this instance!

5)I don't suppose those old Dutch windmills have the same problem, but what do the Dutch know seeing as how they were built almost 200 years ago mostly from stone and wood, and some of them are still running today.
a) The systems mainly used were not fully automatic, but usually allowed the windmill to go sideways to the wind when needed. Some had foldable "cloth" coverings for the sails as well......a look on the internet will show several designs.
You can start here and look at some great photos. The mechanism that lined up the blades on or off the wind can be clearly seen in several pictures. Its at the back on the top, opposite side to the main blades.....the first picture shows it from the side. The impeller, if the wind drives it, turns the windmill into the required direction.....

http://arch.ced.berkeley.edu/kap/gallery/gal082.html

I hope you find my comments helpful. Have a great day.

Der Fisherman.

[jhowelb]

At December's U.N. Global Warming conference in Poznan, Poland, 650 of the world's top climatologists stood up and said man-made global warming is a media generated myth without basis. Said climatologist Dr. David Gee, Chairman of the International Geological Congress, "For how many years must the planet cool before we begin to understand that the planet is not warming?"

I asked myself, why would such obviously smart guy say such a ridiculous thing? But it turns out he's right.

http://www.mlive.com/opinion/flint/i...global_wa.html

[jetpig1]

The whole carbon credit deal is nothing but a scam of a cottage industry that Al Gore expects to profit from. When people like him and Babs who preach global warming stop flying in private jets exhausting more CO2 than I will in my life on one trip in their plane I might listen. Then again, I could never see me listening to anything those blow hards have to say short of goodbye and good ridence.


Bowman

How are they gonna profit ? How should they deliver the message to the world, wooden cart ? You've proven it's tough enough to get through using technology like internet. When you look at the facts of the last 100 years of industry, versus the last million years of earth, big difference. Besides, you can be angry all you want, there's plenty of time left to vehemently deny things until the last gasp... hell, cigarettes and liquor aren't bad for you, that's something we learned in the 50's.....

[handlewanker]

Thanks Fisherman, what a neat way to get aerial shots.

It just goes to show you, THEY (whoever), never considered whether the windmill was efficient or not before it was built, 'cos it was needed to do a job of work, and is still capable after almost 100 years of doing it.

I wouldn't give much credence to the modern designs for windmills (or ANY mechanical or electrical device) that are designed to grab the last ounce of energy from the air, and in so doing are downgraded in the reliability to last department, which means that after about ten years of use the damm things are considered dangerously obsolete and only fit for scrap.

The reason for this is the present day way of thinking as regards to all technology, be it domestic or industrial, someone has to make a profit all along the line and the sooner you can obsolete a design the sooner the new design can be made to be sold at a profit.

There's no profit to the maker if the item lasts too long, and a guarantee or warranty that it won't break before the 12 month or 3 years is up is no comfort to the buyer when it eventually does expire.

But that's life, profits before reliability, and throw away means more profits to be made.
Ian.

[der_fisherman]

You have touched (in a pleasant way of course!) on a "sore point" of mine to do with solar energy for hot water systems. They are generally too expensive and amortization takes too long....
The modern system uses evacuated glass tubes in (expensive!) boxes to get the last ounce of energy from the sun per square meter.
I had a friend many years ago in the UK, who put some sort of professional systems in for houses, but his own two private systems were very primitive in comparison, but cost next to nothing to implement.
For his swimming pool, he pumped the water down over his garage roof, in the open, not under glass even. There was just a sieve to filter out leaves and other stuff and he had painted the garage roof black first. It had a corrugated metal roof.
That was the cycle, out of the bottom (cold part) of the pool, spread out the water over the double garage roof painted black, collected it in an insulated pipe and placed it back in the pool.
A light operated switch stopped the pump during the hours of darkness.
He and his family could swim from March to November some years. In fact, in a hot summer, he had to switch it off a lot otherwise the water got simply too hot.
He did have a "Pool Blanket", bought in the USA for when not in use, to keep the warmth in.....
For his house heating, he used old single house radiators from the scrap yard, repaired and all the paint removed before being painted matt black. He placed these in glass boxes on his roof. He said that they were not as efficient as a purpose made system, but they cost next to nothing and he could add a few at low cost to get the same amount of energy of a professional system quite easily....
I never used his bath, just washed my hands a few times! But he also said, he had mostly enough warm water to keep the house warm and to provide warm water for washing etc for most of the year. I do not remember detail and its a long time ago 70's, but he reckoned that he saved at least 50% of heating costs over a year.....
regards
Der Fisherman

[dynosor]

he had painted the garage roof black first.

How did he keep his garage cool in summer when the pool didn't need its water heated?

[cgosnell]

Cost vs Reliability has always been an issue. Only now do we have the tools (simulation) to fine tune this to the extent we do. At every time in history, builders and Engineers have tried to push the envelope just a little too far... (read 'To Engineer is Human' by Henry Petroski)

I read a quote once that said 'Anyone can build a bridge that will stand. It takes an Engineer to build one that just barely stands..."

[handlewanker]

Fisherman, I remember those home made solar heaters in UK, back in the 70's.

Some of them actually got to boiling point in the summer of '74.

Down in OZ it's a death wish to leave the hose pipe out on the lawn during Summer and then turn on the water, almost scalding hot.

The simplest was just a glass covered box with corrugated iron painted black and the water just ran down the corrugations.

The point is they actually work, no matter for how long during the year, and some saving is better than no saving, efficiency doesn't come into it when it's home made and cost nix, but works.

I think the same can be said for all methods that show a return for zero input, but the current trend seems to be paying lip service to the fact that eventually living off the land, so to say, will be the norm, provided you don't live in a high rise with umpteen dozen others, then you'll just have to pay the bill for energy no matter what it cost.

Air conditioners are a prime example of cost structuring.
8 years ago I had an evaporative type cooler fitted to the roof of my hovel.

It works on the principle of latent heat in the water and when you evaporate water the result is a drop in temperature, (expansion of liquid to a gas) law of physics.

When it's 35 deg C outside it's 25 deg C inside, and you don't get to have stale air recirculated, just continual fresh air, all windows open etc.

The heart of the system is a big fan in a box with water trickling over porous filters, which as the water evaporates, cools the incoming air down and at the same time absorbs any dust on the filters coming in, and this cooled air is ducted round the house through ceiling vents, and all for as little as $1 a day to run.

The fan doesn't require a huge power input, as it only pushes air down the ducting, so the energy consumption is next to nothing.

I reckon the cooler could be run from a photo voltaic panel for the amount of powere it only uses.

I've got a regular refrigerated type air conditioner in the living room wall but that hasn't been used since some time after the day it was fitted, too damm noisy and only cools one room a bit, even at 2 HP, with the rest of the house still hot.

Anything bigger than 2 HP and you need to have a 3 phase power supply put in.

One thing's for sure, I'm not going to my grave all hot and bothered when the solution is simple and very cost effective.

I'm thinking about getting one fitted to the roof of my garage workshop, once I've finished the roof insulation, as it gets to 50 deg C inside during the summer months.
Ian.

[handlewanker]

Cgosnell, to be absolutely correct, the structure is initially designed to take the load, then a safety factor is applied and you end up with a bridge etc that is just like the Romans built, rock solid, no "barely" factors there.
Ian.

[der_fisherman]

I assume you are being funny......
Not bad.
Regards
Der Fisherman

[der_fisherman]

Great post!
regards
Der Fisherman

[martinw]

Dear der Fisherman,

What a pleasure is was to read your polite and measured post. You made excellent points. I, alas, made some mistakes.

"They were probably made of GRP which is not entirely heavy,"

I assumed that all those turbine blades are GRP on a PU foam core, making the overall density not that great.

Best wishes,

Martin

[martinw]

Dear handlewanker,

Evaporative cooling has a lot going for it.

Best wishes,

Martin

[der_fisherman]

Hey, no problems! I like being here and chatting with such really great people as you yourself obviously are......
have a good one
der Fisherman

[NinerSevenTango]

Thanks Fisherman, what a neat way to get aerial shots.

It just goes to show you, THEY (whoever), never considered whether the windmill was efficient or not before it was built, 'cos it was needed to do a job of work, and is still capable after almost 100 years of doing it.

I wouldn't give much credence to the modern designs for windmills (or ANY mechanical or electrical device) that are designed to grab the last ounce of energy from the air, and in so doing are downgraded in the reliability to last department, which means that after about ten years of use the damm things are considered dangerously obsolete and only fit for scrap.

The reason for this is the present day way of thinking as regards to all technology, be it domestic or industrial, someone has to make a profit all along the line and the sooner you can obsolete a design the sooner the new design can be made to be sold at a profit.

There's no profit to the maker if the item lasts too long, and a guarantee or warranty that it won't break before the 12 month or 3 years is up is no comfort to the buyer when it eventually does expire.

But that's life, profits before reliability, and throw away means more profits to be made.
Ian.

Those old Dutch windmills were built for a different purpose, and they were built in a time when alternative sources of energy were just not available. (They had to burn peat to stay warm!) We're talking about technology that dates back to AD 1300 or so. The consideration on profits vs reliability always boils down to the question, "compared to what?". The answer then was, "compared to not being able to live here".

They were very expensive, but once built, they improved living conditions immeasurably. Their development was refined over many hundreds of years. And efficiency was of utmost importance, contrary to your statement above. As for longevity, they required constant maintenance, as you can probably imagine. Wooden gears and bearings, weather, humidity, storms, you name it. The advent of the steam engine almost wiped the old windmills out instantly. They survive today because of the efforts of preservationists.

There is a thoroughly delightful online book on the subject at:
http://www.nt.ntnu.no/users/haugwarb...zen%201962.htm

It shows the different types and most interesting to me, how they work, how they were made, how they were used, and how they shaped the lives and history of the country. I found it fascinating. The most important use was for pumping stations, but they also powered grain mills, sawmills, oil presses, and other tasks.

They did perform some experiments after WWII to see about generating electricity with them. On one of the larger ones, they estimated it could generate about 50,000 KW-Hr per year, but noted that the value of the electricity wasn't enough to justify it.

The book also has very interesting information on the means used for pointing them into the wind, and the devices that were used to prevent runaway in gale force winds.

And oh, by the way Handlewanker, those were built in feudal times, by feudal lords. They were made obsolete by the profit system you decry, because capitalism gives the power output of one of those beautiful machines to any peasant in exchange for a few minute's worth of his menial labor. What once required an entire community to revolve their lives around can now be gotten for a pittance. I'd rather not go back to the old way, thank you very much.

Cheers,

--97T--

[NinerSevenTango]

Dear handlewanker,

Evaporative cooling has a lot going for it.

Best wishes,

Martin

The last place I worked, the water bill was around $1,000 per month. That's a lot of evaporation going on!

--97T--