'Sailing'?? Directly to Windward

FYI, the English speaking world confuses the use of the terms "motors" vs. "engines" as often as not. Most technical types use "motor" for electric to rotary power, "generator" for rotary to electric power and "engines" for fuel powered devices. You are not really wrong in your use, but some may say differently. (Note to the terminology police, the above is an attempt at a polite suggestion for improved word usage. It really does not hurt anything to be nice and constructive.)

As expected, I assumed that the traditional 85% - 90% efficiency motors and generators would have a real hard time beating a mechanical transmission. However, this all changes when you get to the 94% to 98% range you quoted.

I think I understand that when combined with an advanced computer control system, the electric option maximizes your ability to extract energy from gusts and/or just variable wind speed and direction.

A very small amount of storage (capacitors) can absorb any gust surge power and then you put this smoothly and efficiently down at the wheels. The controls and power conversion device act as a very efficient wide range automatic transmission to allow you to keep the turbine speed and/or pitch optimized. It is also much easier to automatically achieve optimization of wind turbine aiming.

Another part of your discussion is also no surprise. Yes there are high tech devices, but they are really not readily available in sizes that make it easy for a DIY or prototype effort. Considering how much energy is wasted on standard efficiency electric motors world wide, it is a real shame that large production facilities are not being shifted over just because it is the right thing to do.

I did get a little lost in one area. Are you planning on using two drive motors in addition to a turbine powered generator, or are you planning to use one wind turbine powered halbach array generator and then a separate halbach array motor for power to your wheels?

 

Ingmar,

On a separate note (just to be honest, this is has only minimal boating involvement), I have some ideas that may be of interest to a student playing around with harnessing wind energy.

I am an engineer that has been in the energy industry for over 30 years. I see a lot of "green" stuff that just does not make much sense when you consider the really big picture. You have to think cradle to grave. This is the cost of obtaining raw materials for devices, cost of making devices, cost to distribute and install devices, cost / effort to maintain devices, cost to recycle or dispose of items (especially batteries). When I say cost, it is not just dollars, think of energy used, ground disturbed, waste created, etc.

However, wind power is really one of the best "green energy" areas for individuals to both explore and exploit. Small scale "back side of the house and up on the roof" turbines are not overly obtrusive and would be considered by quite a few. The same technology actually has even more value for some boaters in a marina or general at anchor setting. More use and more benefit could be achieved with:

• Better turbine designs worked out and made available in a range of options ("some assembly required" kits with all required parts for quick results, kits with only "hard to make" items supplied, and DIY plans only)
  
• Efficient (but not overpriced) conversion for rotary to electric.
  
• Good electronic controls and good power conversion devices.
  
• Better options for what to do with your power.

The last one probably is getting less attention than it deserves. Unless batteries are already part of the picture (i.e. you own an electric car) I am not real fond of batteries when I consider the really big picture discussed above. I am also not real found of conversion to household AC to supplement grid power for a number of reasons.

An alternate use would be to drive a compressor. A compressor combined with a smart integrated control system could provide space heating, space cooling, water heating and food refrigeration for household needs. With modular components, this approach would really not cost that much more but to greatly reduce household energy usage. With a compressor and refrigerant cycles, energy storage can also be easily built in.

Another possible use in conjunction with a compressor would be to go for simple high pressure air storage. Consider compressed air as an augment for traditional automotive uses. A compressed air/fossil fuel hybrid should be an easy engineering effort compared to the electric hybrids. A big reason compressed air is not being considered more is due to the poor overall energy efficiency and cost of electrical grid powered compression of the air. However, if you have most/all of your compressed air coming from your own wind turbine the low compressing efficiency is overcome with the up front sizing of the turbine. This technology should have much lower long term maintenance concerns than any of the other "green energy" options for automotive applications.

 

That is an interesting approach. Many of us use air tools in our shops in a daily basis.

 

Many small businesses use lots of shop air. More than a few would cringe if someone showed them their true energy cost. Reasonable payback for a conversion to a wind powered air system should be achievable.

For home shops, few would be able to break even in converting over. Even so, if good kits and/or DIY plans were available, some probably would just for the sake of it.

I actually thought of this a while back when one of my boys got into paintball. The amount of energy stored in a small 5000 psig bottle is astounding. Some jobs that would be a real struggle for a battery powered tool would be a breeze for a tool with one of these bottles. Also, the bottles do not loose capacity as they age. The short life and cost of portable tool battery packs drives me nuts.

 

A splendid, refreshing attitude!
My colleague describes some of the "hidden" costs and difficulties with installing large wind turbines in:
http://www.cyberiad.net/library/pdf/ringdrivevawtsept09.pdf

A couple of years ago some Australian proponents were proposing large offshore wind farms as if this could be done using off the shelf components. They didn't realise that (at that time) there were only two sea cranes capable of erecting turbines of that size and they were both in the North Sea.

 

High Tacker www.damsl.com

Wind powered air compression! Now we're talkin'!

And now back to boats. For years I've thought that a wind turbine driving an air compressor driving a boat, straight into the wind as well as in any other direction, would be the ultimate wind machine. Fart the boat right along, and for free. Great for maneuvering: just point a nozzle in the opposite direction to where you want to move the boat, bow thruster, stern thruster. Good for heating and cooling, filling your dive tanks, running air motors, air tools for whatever you want to do. No batteries. Long life. No sparks. Not much to maintain...

Actually, it might be better to turn props with air motors...I mean, rather than just fart the air out...run the air through the prop, and I think it could be designed so as to eliminate ordinary prop cavitation in the process.

The very mast for the turbine could be one very long axial air compressor. Of course that wouldn't yield very high pressure, but you could also have a piston-type compressor at the base of the mast, for highly compressed air for storage.

Another part of my idea was to have the air intake come through perforations on the leeward surfaces of hollow turbine blades. Remember the kind of modified Flettner rotor, kind of modified Magnus effect that was used to drive Jacques Cousteau's boat, the big cylindrical sail. It had a big, powerful exhaust fan at the top of the cylinder (powered by a diesel motor, I think about 12 hp) that sucked the air out of the cylinder and sucked air in through strips of perforations on the after quarters of the cylinder. A moveable flap covered the windward perforations so that air was sucked in on the leeward side, creating a pressure differential between the windward side and the leeward side, voila!, an airfoil. Thus can a cylinder become an airfoil.

I think that if you start with the best airfoil shape in the first place, and a hollow one, and then perforate a strip along the leeward surface, behind the curve of the camber, and suck air in there, then you will improve the lift to drag ratio considerably. So, once the turbine starts turning, the fans along the axial compressor down through the mast will draw air in through the leeward surfaces of the turbine blades, hence a more efficient turbine.

My problem is, I invested in too big a boat and then ran out of money to experiment with, and indeed, now that real estate has turned to crap, I need to sell my boat for money to live on. But it would be great to see some students do something like wind powered air compression. So I'll throw in my ideas on such a project, free gratis for nothing, just on the off chance of seeing something happen along these lines.

 

Leo,

I had previously read the web page you provided. Large scale wind generation is booming, but the world really ought to be investing in technology advances prior to wide scale deployment. It seems like such a shame to invest millions in a huge wind farms only to find out that equipment failures keep a huge fraction out of service and the maintenance cost just keep eating away the hope of quick payback.

High Tacker,

Going from wind to compressed air really only makes a lot of sense when storage is important or when you need to have compressed air for some end use.

For direct use on the water, I would see an advanced electric drive enable some significantly different approaches. Consider the following:

The wind turbine can have the generator supported by a structure that does not need to be concerned with gear boxes or drive shafts. This would allow a three hull boat (one in front, two to the sides) with a wide stance and a light but strong tripod support for the generator. This configuration would be much more capable of dealing with the flywheel issues that you spoke of previously. Each hull could be rotated as you want to change boat direction with respect to true wind direction. The tripod, generator and wind turbine assembly are always in the same constant alignment with the apparent wind direction. Electric drive can be distributed with a prop unit at both rear hulls, or a unit at all three hulls. Computer controls for variable pitch and power conversion can keep both the turbine and the props operating at optimum speeds.​

The above should perform very well full scale where the structural advantages would come into play. Cost and project risk would be a real concern unless funded by someone with deep pockets.

However, a smaller scale demonstration craft could probably be assembled as a spin off from the land based competition that prompted this line of discussion.

Actually, full scale is probably not even worth starting until the required turbine, high efficiency motor drives, high efficiency generator and power conversion parts all become something that can be purchased ready to use. You would not want to be deep into development of these components at the same time as assembling the overall platform.

 

High Tacker www.damsl.com

P Flados,

Although I didn't say it in so many words, storage of energy was perhaps my main consideration, and I did after all mention heating and cooling, dive tanks, tools, long life, etc. But you're right, for direct use, certainly in a racing machine, compressing air and immediately blowing it out for propulsion would not be as efficient as mechanical and now possibly electrical means.

Again, of course, I didn't say it, but was thinking of a cruising or work boat, not a racing machine, never mind that I brought it up in the context of throwing out ideas for these bright young students to work on, sponsored by somebody with deep pockets. And thanks for reminding me that racers tend to get more funding. Did you know that race car drivers are the most highly paid "athletes"? Uh, I wonder why greenies aren't out there protesting at motor races where more fuel is burnt in one weekend (and without all the catalytic converters, etc., for pollution control) than by all the commuters within a 500 mile radius in a week of getting to work...could be that discretion is the better part of valor, scared to death of them redneck hotrodders, are they?

 

Where did you get that estimate from?

 

From before the preposition but from the back of my pea brain. What would be your estimate?

 

"According to NASCAR, about 6,000 U.S. gallons (~22,700 litres) of fuel are consumed during a typical Sprint Cup weekend.[19] For the 2006 season, which included 36 points races, the total for the season would have been 216,000 U.S. gallons (818,000 litres)."

so 6,000 gallons. Now Think of the Nascar/football tailgating audience with trucks. Fair to say that 20mpg is not pessimistic for their driving. Seating capacity is 90,000-150,000 on the tracks. Even if we throw in outrageously optimistic 4 people per car its easily 25,000 vehicles. And 20 miles driving distance again is stupidly low - but that would make the math simple and mean that one race would spend 4-5 times more in the fuel spent in getting to the track. When you take more realistic 40 miles distance, 18 mpg and 2 people per car (100,000/2*40/18) you get 111 111 gallons spent in fans driving vs. the 6000 spent by race cars.

Obviously the fans spend the fuel even if its not nascar but horse racing, football, soccer, motocross...

 

"Pea" seems reasonable.

 

High Tacker www.damsl.com

kerosene,

Holy Cow! Thanks for the supporting numbers. I repeat: Where the hell are the greenies when they're really needed? But, uh, did nascar happen to give the numbers for all the support vehicles, etc. I don't imagine all the race cars got there under their own steam, not to mention their myriad attendants. And what about all their test runs, etc.? At any rate, the wind-powered-vehicle guys do seem to set a somewhat better example for their fans.

Cheers, High Tacker

 

High Tacker www.damsl.com

Hey, this time I tried to tailor the analogy, so that I couldn't be accused of talking down to the audience. Glad you got it. But I neglected to say that the back of my pea brain is located somewhere near the seat of my pants.

 

Sure the circus going around takes lots of fuel but gain that is the same for a football team flying to a game etc.

My point is that on value level racecars might promote irresponsible fuel burning but in reality the masses moving is much more relevant challenge. I do think that setting (reasonable) fuel limits on racecars would encourage more RnD that can trickle down to real vehicles.

Then again nascar engines are still pushrod V8s - the rules don't exactly encourage innovation.

unrelated - and I am starting to feel guilty for derailing. I tried to get calculations for concrete walls needed for lets say 20 bar pressure tanks. My parents run a farm that has high variation in energy needs - wanted to make calculations of cost of relatively large (several cubic m) pressure storage. then have solar or wind or whatnot pump into the tank at their own leisurely pace. Doubt it makes sense in the end. But there is real need for sensible way to have energy cache.

So far the best ideas (I think) I have are more in the range of passive solar. Just because the costs of investments can be low.