Water as Working Medium in Wind Generation

A loose helical coil of hose would allow for ample rotation, but why limit to <360 why not allow for 540 degrees with a return device ? I think a concentric hydraulic joint would be the best solution there. Also, the falling weight of the fluid should largely balance out the rising side leaving a relatively large amount of hydraulic energy for the MG. I am intrigued by the idea, but wonder what the mass / energy limits are for the pump, does the mass / energy really compare to the top loaded generator ? The post says Viable, but I assume viable to mean possible not necessarily desirable. My concern is that hydraulics are notoriously leaky. perhaps the entire inner tube could rotate and the pesky rotating couplings be at ground level as well, with the rest robustly piped. Then the only thing at the top would be the pump and vane controls. A second hydraulic pump connected to the motor at the base end could send the fluid back up to the top. As to the choice of fluid, I guess anything earth friendly would be a good choice. Water may be too thin a medium to seal well. Interesting.

I like your way of thinking. The progress made in the last ten to fifteen years on hydraulic motors makes this option look a lot more desirable with considerable power output available (some are used on large trucks).

Certainly having an annular pipe that rotates with the inner bearing race of the vane control (turbine orientation) makes good sense. Then those "pesky seals" can at least be reached without climbing all day.

Must be a reason, else the current designs would be using it ??

Perhaps the separation of the drive rotation and the swivel of the head end were non compatible ( helicopter without rotor )

Wouldnt the shaft be kind of massive ?

One of my buddies at work here at the power plant mentioned that idea, and certainly it has merit. Obviously, this is going to have someone who knows about long drive lines design that part, and I suspect there is going to be an issue on one over 100 feet in length (height), as there would have to be stabilizing bearings (like the throw-out bearing on a two part drive shaft on a blazer?) every so many feet. Otherwise the materials for this driveline would have to be high-tech stiffness and high torsion modulus as well. I still think there will be a number of parts, but in the end, there is a good chance of saving weight load on the tower. Weight load translates into torsional impulse during gusty winds, does it not?

those bearings are called "carrier bearings"why not run one through one of the support legs?

Why not..indeed. Good going. Let's see: your concept gets a gold star since you go from shaft rotation to shaft rotation at same speed (put any gearbox at ground level), but one shaft is horizontal, and has to converted to vertical with helical gears? Kinda like the rear end of that Ford pickup. Then the mechanical motion can be direct into a vertical design generator (different bearings etc.). No water, no hydraulic oil, etc. Very conservative thinking, that I like.

it's KISS" THINKING........keep it simple, stupid!

Does distributing bearings along a long vertical shaft inside a long pylon follow the KISS concept ? how would one inspect/ maintain them ? l agree some kind of guide or support would be required at intervals, to prevent harmonic vibrations whipping the shaft out of position, it would necessarily be balanced as well. IMHO, limiting the inner tube to carrying the hydraulics from top to bottom is way more KISS than a drive line.

sure it would be balanced but keep in mind this is a low RPM application. inspection plates could easily serve for maint inspection/service.

Everything is possible, but it is very impractical:

More parts, the shaft and bearings just add to the list with no benefits. More material to construct the top head, the tower. And where will the ladder be, or the elevator?

Mechanical:

When you do the math for a 100- 150 m long shaft, you will see what diameter you'll end up, especially to take care of the high torque at low speed.

Say a moderate 5 MW turbine generates 6,700 HP. The tips of the wings reach speeds of 180 Mph. Up there you move a few meters sideways too. That spindle would be a massive experiment, or it will twist, or otherwise the tower will.

Fatigue and torsion will be a permanent headache. Serviceability wiped out.

This is a totally different task as with the drive train of truck and trains. (RPM)

A lot of manufacturers even put the HT transformer up also to gain momentum.

Electrical:

Power to position into the wind is available upstairs. Same for the pitch controlling servo motors. Otherwise everything has to run from downstairs.

A spindle at high RPM makes more sense to me, but remains very impracticable.

The hydraulic pump would be mounted in the top of the support column with the drive shaft extending only the distance from the propeller axle shafts to the pump drive axle connection, just a few feet. The only thing in the propeller shaft housing would be gears, axles and bearings.

Doesn't matter which way the wind blows, the top part is drive train only and can rotate 360 endlessly since the spider gears are designed to work that way.

Putting the hydraulic pump in the head using the hydraulic fitting from a loader works as well but then you are adding something else to wear out.

Thanks, hydraulics work also best at higher revs. Now it is "direct drive" minimal losses. There are some good videos on Youtube

What is inside a windturbine

If you are referring to my post then be aware I was trying to compare the mass to power ratio of a generator to that of a hydraulic pump.

You should ask yourself what gives out first on the current wind generator designs. Now knowing its the gearbox, and/or generator, why in heck would you want all that stuff way up in the air? Not to mention the switchgear on one of the new DC-> AC designs.

If the current gearbox design is inadequate, beef it up a little.

Or....we could redesign the whole shebang, throwing in more component systems in the inefficiency chain before the light bulb comes on.

I'm in the camp with the beef.

Whether a Hydraulic pump or a vertical transmission shaft, you still need a hefty gearbox up in the air. And that needs service and also prone to breakdown.

If you want the top gearbox to run at aslow speed, then the vertical shaft will need to be heavy in diametre. etc

The problems are still going to be there! the only part that will more accessible for maintenance will be the generator (which needs the least attendance) if at lower level.

Depending on efficiency, KW ≈ gpm × psid ÷ 1000.

Thus there must be a combination of rather high pressure and flow.

It does not actually go that simple, there is either a gearbox to parasite away some energy as heat and wear, or a DC-AC converter panel upstairs in at least one new design I have seen published.

Without gearbox or hydraulic drive can a specially designed generator direct coupled to turbine give voltage at variable frequency to be rectified and inverted to required voltage/frequency?.

I guess you could use water. The drawbacks far outweigh the benefits though. If it were me doing it, I would be predisposed to using a rotary actuator to position the props. Not being totally up to speed in windmills, it is logical to use similar practices used in solar tracking to get maximum use of the wind. As for fluid selection, I would use H1/H2 mineral oil. It has good lubricity characteristics, good heat tolerance, and relatively stable viscosity properties. Choices are abundant as to how to skin this cat.

<...H1/H2 mineral oil...>

....and it doesn't freeze-up - an important consideration for remote, unattended equipment at higher latitudes.

There has usually been ample money for a different or new design, as long as a profit could be seen or it is obviously of some advantage (usually the former ). Anything is possible if you throw enough money at it, and anything can make a profit if it is done well. ( barring socio-political-fanatical interference )

I, the OP, wish to point out two things: I am giving out free good answers, because I did not see any bad answers. This was meant to stimulate thinking about two things: (1) can wind turbines be improved upon, and could water be actually used as a hydraulic medium in these, and (2) is there an obvious way to improve load leveling of wind farms by introducing local energy storage?

I think now we have a formulated answer: (1) yes - improvements can be made and are being addressed, and no - water as a hydraulic medium is not the answer - mainly due to leakage issues and freezing, (2) local energy storage is possible, but the better way might be to leave the wind turbines alone, and put in a central hydraulic accumulator station to store up some off demand wind energy for load leveling later when the wind drops off. Or use other energy storage such as lifted weights or hydro-pumped storage to man-made elevated reservoirs or compressed air, or flow batteries (redox reagents are pumped over the electrodes).

I wish to thank you for your good answers. Honorable mention goes to Fredski for support of his idea to use vertical driveshaft (that my buddy at work also mentioned to me earlier). Seems to be this would have to be worked out as to (1) savings of materials needed on site, (2) would the shaft actually have to be turned rapidly to lower the torque on the shaft (not my area of expertise)?

This actually got me thinking about another idea: suppose now you simply have the main turbine shaft powering a 90 degree gear box coupled to an axial air compressor? The compressed air could be then piped to the ground easily, since the vertical gear box shaft is able to spin around with the wind turbine orientation.

The option now becomes a choice to put the compressed air in storage directly, or use it to immediately drive the generator through an air motor. Two other points: if such a compressor is used, then heat dissipation is needed - might was well drive a heat engine off this, as the temperatures are not negligible. The heat engine (not saying what kind or class), would be used to produce additional compressed air, or shaft power to the generator. Any water condensation resulting from cooling the compressed air might be useful for local livestock watering, or irrigation maybe.

I will be surprised if anyone agrees with this idea.

IMHO I would use air for speed and flexibility, and Hydraulics for brute power. I believe you won't really be too surprised, lol. an interesting exercise.

Actually I kind of like this answer. It addressed the biggest problem with air...the heat which would need to be dumped or used, and the water vapor problem. The water vapor will be contaminated with oil, so it will need to be disposed of properly. Might in the long run be cheaper to just use it in a closed cycle.

(I just let mine evaporate on the top of my compressor. Helps keep the compressor head cooler as well. Sometimes it gets scary hot during long sandblasting jobs.)

Ever measure yours with a IR thermometer? My big 15 HP will hit ~350 F on the exhaust ports if ran long enough!

No. But I did melt a plastic bottle full of compressor oil I had forgotten I had left there....

A friend of mine here built a VAWT using 4x8 plywood panels, and used a 10' x 1.5" shaft to a hydraulic pump, and when he closed a valve to see how much pressure developed, sheared the shaft. Further development was halted due to his demise. (unrelated to this experiment)

You just looking for ways to transmit power from up there to the ground without using electricity?

Well, you "could" drive a slush box which would heat up the hydraulic fluid and you could then pump it to a boiler on the ground. Or use it to dry grain, or heat the barn. Imagine, a windmill without a generator on it!

You could pump water with it. Now there's a novel idea! Wonder if anybody has thought of that. Or maybe grind grain! Drive a trip hammer.

OK, maybe it could be used to put an edge on flint shards also. Or better yet, a whole obsidian blade factory. I don't think the obsidian gattling gun has been invented yet, either.

Certainly, if we talking heating the barn, then this is something the Amish would glom onto. Heat on windy winter days is not a real bad idea.

For that matter, I don't know why the vortex wind turbine idea (was it Cornell University?) back in the 1980's?? was abandoned. The concept was to build a multi-megawatt machine using a cylinder of movable slats (the cylinder kept stationary), but upwind slats opened slightly off to one side, and on the leeward side off to the other side. This was to induce a vortex, and spin a vertical axis rotor at high speed.

Maybe the tip speed was excessive based on the size of the design. The Michaud brothers have published their relatively new design for a solar/waste heat, with wind for what they refer to as atmospheric vortex engine. It appears they want a much higher megawatt output, presumably by placing numerous turbo-generators (high speed horizontal wind turbines of small diameter) around the periphery what looks like a natural draft cooling tower (which apparently can still be used as such). Two for one special on aisle 9.

Your tag line says it all..

James Steward-

One major problem to be overcome with the hydraulic prototype is in a hydraulic system the pumps are usually located lower than the motor to avoid air lock or air in the hydraulic circuit. Since air is compressible it would have a very large "knock" force as it exited the motor as the pressure quickly reduced and the air expanded.

One potential solution might be the placement of expansion tanks or other suitable components in strategic locations.

Good Luck, Old Salt

<S> (Salute), thank you and all the others for your considered replies. I am about ready to abandon any non-compressible fluid - based on several consideration, and simply revert back to a more environmentally friendly (and engineering friendly) system that will simply use air as the working medium.

I think the only good way to do the conversion/storage of wind energy with hydraulics will be pumped storage, hydraulic accumulators, etc. Electrons might be just fine to drive that, much more experience available there. OR one could even make a throw-back mindmill - rotor as normal, gearbox like the old Aeromotor windmills, and plunging rod design, except the rod drives a positive displacement high pressure pump at ground level, thereby eliminating all the other problems mentioned.

Now I am not stating this will instantly take off, but the main idea is storage of energy, demand leveling, and operation to at least some extent during wind outage. There will be a niche for this, trust me.

Run an aircompressor by windmill & store the energy to drive a generator.

A friend of mine above Royal Gorge uses a 3 blade (appx. 4' dia.) to run a 2 cylinder air compressor.... the air line runs about 300' to a large tank (500 gal. or so) in his shop (supplies air for shop), then about 600' down hill to a well (300'deep) to a 'percolator' head which carries water teaspoon at a time to a tank about 50' above the house for household use....I don't think he's considered air for electric as he has solar and wind powered generators charging batteries.

Seems like your friend has the energy thing on like donkey kong. I like his water pump idea, but does that (1) innoculate the water with airborne bacterials spores, and (2) take a great deal more air to operate than it should if he used an air-driven water pump - the water well pollution abatement folks use these quite a bit for low flow applications. I like the big old air tank idea. Might be fun to see what else he comes up with. Usually the smart guys are the ones who have to figure it out seriously, or do without.

He uses an old propane tank for air storage, as I recall he flushed it several times about 20 years ago...the air that goes down the well is filtered and regulated and moves the water to a redwood tank above the house. The house is a steel building with double pane glass on the south side facing the Royal Gorge....looks like a blue cube on the mountain top. He's had several lightning strikes over the years, taking out a generator but no other major damage.

Pretty cool set-up. I remember going to the bridge with my folks as a youngster, and it was an impressive view for a flatlander from the "semi-desert".

Just mount a differential with spider gears on the rotor and the hydralic pump at the top of the tower. Then you could mount two rotors like the Volvo marine outdrives have and get twice the power.

Interesting. Do you have a link to the differential you included as a photo?

I think (imho) that the approach of using sails, wings, and various devices to create high rpm to drive generators and air compressors fail when applied to hydraulic pumps and motors. A VAWT, low rpm, with a 'flat plate', at right angles to the wind, on a long lever arm, would provide maximum torque and power transfer.

That's just a CAD image of standard automotive differential spider gears. Called Posi-Traction by GM.

I have always wondered why the tower itself couldn't have a few vertical axis wind turbines mounted on them towards the top.