A Personal Turbine Makes Your Rooftop Into a Wind Farm

Can someone help me with the math on this?
1500 kWh/year
Local cost ~$0.12 per kWh
So I can save 180$ per year.
$10,000 (usd) for the unit installed.
Recovery time.....$10k/180.....55.5 years!

Could it possibly be 1500 kW per month? Am I missing something?

For 100 bucks a year I don't think I'll bother.

For me at a savings of 22 dollars per month or 15% of my electric bill, to the initial cost of $10,000. I will not be buying one anytime soon, thank you. ;)

This must be subsidized by our governments at a rate of minimum 50%. Also governments are giving us the option to not reduce, reuse nor recycle. It must be the law that every household have such a turbine. Also, why are appliances ALLOWED to consume ghost power. Back in the days when you hit off it actually meant OFF now its standby... Again it should be illegal for companies to make appliances like that.

Compost and Recycling should be LAW..

Crimes against nature..

Fair point mrlegoman.

As a business case, youre entirely right, it doesn't make financial sense, but you're assuming power will always be readily available.

But What happens if:
1. Massive solar flares take out the Electricity grid as predicted in Popsci.
2. Aldronslasthope is right and our reticulan overlords return to enslave mankind.
3. Hippies get their way and we switch from nuclear to wind / solar energy only to realise the difference between peak capacity and demand.
4. Tesla is proven right and electrons in fact, do not exist.
5. Zombies, never forget about the ever-present threat of Zombies.
6. Sarah Palin makes it into the white house.

Then youre going to be kicking yourself for not buying it when you had the chance.

PFHAHAH " harvey loving it

Well, if this thing will help me use my laptop, blow dry my hair and cook my pop tarts, perhaps it has some use;..... after I will the BIG LOTTO of course. ;)

The $10,000 estimate includes installation which arguably could be half of that. If the boxed price is ~$5,000, and you could install it yourself, it makes better sense.

I actually have an waaay off-grid application where something like this could maybe work. However, I'd need very good data on wind speed vs. power output and DC voltages since I'd be charging a battery pack with it.

"Plus, the generator is positioned at the blades’ center, which moves at one tenth the speed of the periphery. And less speed translates to less power."

Do what? They're both rotating at the same speed, this statement makes no sense.

@sickness. they are both doing the same RPMs but the speed on the outer edge of the turbine is much faster. The ability to capture the speed must translate into more power...don't ask me how. haha

Also, if it picks up such a slight wind, this should probably be replacing large commercial wind farms. Based on this article, it sounds like they make more power with less wind.

bildan, it does charge batteries. I imagine you would probably just tap directly from the batteries than use an inverter. You would probably want to contact Windtronics for the wind vs. power output data that you want.

a Direct Current Current? Nice!

Why one earth should any government waste money on this deal. Don't get me wrong, I'd like to own a wind generator myself but industry should lead the way in bringing to market the power for the consumer. Why do people think those idiots in Congress know what is good? Should be law stupid people quite whining to Congress and get off their duffs.

A Massive solar flare will destroy this just as likely as your power grid.

Today Wind Turbines are killing millions of birds and bugs. A better green solution would be to find ways to reduce or eliminate that danger to wildlife. I have been trying to the the US Fish and Wildlife Department to investigate an proposed use for small LED lights in the rotors of wind generators to help protect species. LED could be tested under various wavelengths to determine if and which may warn birds away from danger.

I have researched this product for a while. It is a good idea for limited uses. It can not replace grid power. This product has moved the generator parts to the most outer ring. In this design, the velocity of the moving parts to stationary parts are a function of the circumference. The outer ring is moving faster in measured speed than a point near the middle. A common wind generator of this size would have a small stator and rotor.

I've looked into this a bit as it's been out for a few years. It doesn't seem to be all it's marketed to be. And Honeywell had nothing to do with it. Windtronics is the company, and they use the Honeywell name under license.

This is a pretty good critique of the product:
http://www.wind-works.org/SmallTurbines/Windtronics760EstimatedGeneration.html

Basically from what I understand, the placement of the magnets doesn't really matter. It may start spinning at 2mph, but it will only generate 2mph worth of power. Marketing doesn't change the laws of physics.

They say you can mount it on your roof with a 10 foot pole, and I suppose you could. But unless you live in the country you won't get enough wind. And if you live in the country, you could put up a much larger turbine anyway.

Also, I've seen this thing in person. There's a guy around here who owns an RV with Windtronics all over it. It has one of these on the roof. It folds down against the back of the RV while driving. I've seen it deployed a few times, but never seen it spinning.

I took a closer look at it one time at a truck stop. It's all plastic. It feels pretty cheaply made. For a wind turbine I guess. I'm sure it's more durable than any plastic thing in my house, but that's not saying much.

There have been so many different turbine designs over the past few decades. There's a reason 2 and 3 bladed designs still dominate. They just work the best.

@cober319
You can't explain it because the statement and logic are flawed. It doesn't matter how large the blades are and how fast they move through the air, the generator at the center will always do 1 rotation for every rotation of the blade, barring any gearing. The fact that the blade travels more distance in the same time means nothing.

The only speed that has anything to do with generating power is revolutions per minute of which the blade speed at the periphery as compared to the generator's rotating speed means nothing. Each rotation would still generate the exact same power regardless of the length of the blades and the difference in movement speed between the two.

Sickness... I haven't heard someone say 'Do what' in so long I can't remember the last time.

Imagine for a minute, standing on the surface of the Earth, like we do, you will come back to a certain point in space in roughly 24 hours, because like the Earth, we are moving at roughly 1040mph; now consider how fast geostationary satellites must be moving to stay in orbit above our planet, but they are essentially motionless in relation to the ground.

Another way to put it might be, lock Mercury and Neptune to a certain 'spot' on the sun which doesn't move, Mercury moves at speed X to stay directly over that spot, and for the sake of argument, takes a single day(88days) to go around the sun once... how much faster would Neptune need to be to stay over that same spot? Neptune's orbit is hundreds of times bigger, so it needs to go hundreds of times faster....

'Do what'...... cracks me up! And so a point on a large circle, connected to a smaller circle, must traverse more distance in the same amount of time, the only way to do that is with more speed.

The point being, a larger circle embedded with magnets, will provide more charge for the same RPM, compared to a smaller circle... simply because there are more magnets to induce a charge with. To get the same charge induced by a smaller wheel, you'd have to spin it a hell of a lot faster.

People like MIDOMAN should be banned from voting on account that they will vote away everyone elses's rights. BTW, rights cannot be voted away. Anyway, when you say that the government should subsidize anything...what you really say is that you want your neighbors to spend their hard earned paycheck on worthless crap and you want a portion of that amount to be eaten up by the 3 headed dog of bureaucratic nightmare that is our federal government. There are of course a few things wrong with government subsidization. First, it subverts the free market and sends it mixed signals and causes huge upsets like the housing bubble and the current mess over at Solyndra solar. Second, it is an over reach of the Constitutional power to regulate interstate commerce. Thirdly, it is theft on a grand scale and theft is bad point blank. The government has no right to take from the American people any more than it needs to defend this nation and enfore its constitutionally sound laws (aka, about 1% of the current laws).

I hope that one day you try to tell a good ole boy what he has to do or buy and he punches you straight in the suckhole. I know I would.

Protecting the environment through laws pertaining to resource usage IS part of the responsibilities of the U.S. government... why punch someone for seeing a problem and suggesting a solution to them?

@shutterpod

I understand perfectly that objects closer to the center of orbit move slower, but this has nothing to do with power generation. I'm not disputing the fact that this design is more efficient, and your example with more magnets isn't what they said at all. I'm disputing the original comment I quoted, that the generator in a standard design moves up to 10% slower and slower means less power. BS. The power is generated by revolutions of the generator and it wont matter if the blades are hundreds of feet long and moving through the air at several meters a second or if the blades were smaller than the circumference of the alternator. Each spin of the alternator either way will generate the exact same power.

In fact, going by the logic in the statement, if you extended the blades length exponentially the difference in movement speed would be greater and thus there'd be a greater loss in speed and power generated, right? Wrong, each rotation would still equal the same power but with larger blades it would probably rotate faster and thus generate more power over the same time.

It is innovative, but I agree with the 55 year R.O.I. (return on investment). I can't see it producing more than 1500Kwh's per year because of the low swept area.

The swept area of a 6ft diameter is about 28 ft. Increased diameter increases the efficiencies of all turbines. For example, a 20Kw traditional turbine is about 30ft in diameter. It will produce max about 28 watts per sq ft of swept area (20Kw or 20,000 watts \ 706 sq ft or area of a 30ft circle).

General Electrics' 300 ft diameter, 6Mw turbine however will yield 88 watts per sq ft of diameter (6,000,000 watts\70,650 sq ft of swept area).

Even at 88 watts/sq ft, 28 sq ft only yields 2,464 watts MAXIMUM. It seems Honeywell has mis-labeled it a 6500... this is mis-leading as there is no way this turbine is more efficient per sq ft than the GE unit.

More likely it is in the range of 20 watts per square ft MAXIMUM and this puts it in the range of 560 watts MAX.

There was a turbine made in Ohio very similar to this which was a miserable failure. I would suggest looking at a unit that is being developed by Majestic Wind Technologies, LLC.

It is scaleable capable from 162 sq ft swept area to 10,000 sq ft of swept area , can be roof wall or ground mounted and 'processes' the wind in a way that accelerates air-flows prior to driving the turbines.

So at $10000 ... a $140 a month energy bill or thereabouts ... Saving 20 percent ... Well gosh, I'd make my money back in 357.14 years! ;p~

Sickness, let's put on our thinking caps. Any windmill designer has a problem with how fast the magnet flies past the coil to generate current: too slow, even at great torque, and the alternator is not going to put out much. So, would it be a good idea to place the magnets around the PERIPHERY of the windmill wheel or drive it off the shaft at the center?

Yes, you *can* gear the shaft output up to increase the rpms; you could even construct a big disk style alternator behind the main blades (not sure how you'd keep it from fouling the air flow). But the designers decided to use the existing mill wheel to save money, up-tower weight, not lose power in gearing and gain some performance at lower wind speeds.

[no physical laws were broken in this explanation]

This thing is little more than an automobile alternator with a
propeller that is connected to a battery.
$10,000.00 for that is obscene.

Earthtronics is doing a great (albeit unintentional) job of discrediting rooftop wind power, but don't let their incompetence fool you. As others have noted, most small wind turbines don't use gear boxes to begin with. For example, Sunforce has a 600 Watt (at 12.5m/s) turbine that sells for about $600. http://www.smarthome.com/68021/Sunforce-Products-45444-600-Watt-Land-Wind-Turbine-Power-Generator-with-MPPT-Charge-Controller/p.aspx

Of if you really want cheap wind power you can check out things like the "wind belt" (described in popular mechanics, btw) which is targetted at costing $2 to $5 for charging small devices in the third world.
http://www.popularmechanics.com/science/energy/solar-wind/4224763

Personally, I'm still waiting for the Jellyfish Windmill (reported in PopSci back in 2007) to make it to market.

@Sickness
It's probably a mistake of a non-physicist, it's not the RPMs that will increase the efficiency, it's the distance. The end of the blade covers a much greater distance in the same amount of time, which means not only can more coils be placed for the magnets to pass, but also the magnets will pass each coil faster than it would at the center, because the coils do not(i presume) increase in size relative to distance. Since kinetic energy is (1/2)mv^2, and velocity is distance over time, the kinetic energy at the end of the blade is greater that that at the center. RPMs are what matter in an axle based generators, however once both the magnets and the coils are removed from the axle, it becomes a matter of radial velocity.

@bobbyg,
A car alternator is often designed for too high RPM to be useful for small wind generators, because you have to gear them up and too much energy is lost to friction. You can build a permanent magnet generator from hard drive magnets and a car disk brake that will be pretty efficient though. For blades, a lot of DIYers are cutting them out of sections of PVC pipe, which gives you strong, aerodynamically curved blades that are light and dirt cheap. For maybe $500, some of these guys claim they are producing 1Kwh turbines, which would cost ten times that much to buy commercially.

@daddyvortex
Why don't we first put on our reading caps? Let's concentrate specifically where I stated I wasn't disputing the efficiency increase in the new design.

"Plus, the generator is positioned at the blades’ center, which moves at one tenth the speed of the periphery. And less speed translates to less power."

Perhaps their point was in reference to the new design, but this statement reads as the fault lying in the speed differential between the blades and the armature and implies that a higher differential in speed (increasing blade length) would just make it worse, which is false. When comparing 2 conventional designs with the exact same generator and different blade lengths (thus changing the speed differential)- If the rate of revolution doesn't change, then the power generated won't change either.

@Protagorus42

"RPMs are what matter in an axle based generators"

This is exactly what I've been saying, I wasn't comparing the two designs, I was simply pointing out the faulty logic in the statement I originally quoted.

"Plus, the generator is positioned at the blades’ center, which moves at one tenth the speed of the periphery. And less speed translates to less power."

If you have 2 conventional designs with the exact same generator assembly, one with 5 foot blades and one with 50 foot blades and they both spin at 30RPM they will both generate the exact same power. It doesn't matter whether the difference is 1/10th or 1/100th. This "speed" difference means nothing in a conventional design.

Honeywell WT6500 is at the moment $5,495, not 10,000.
@Honeywell Store.

The Chinese are loaning the US at 4.26% interest for long bonds.

This turbine needs to cost $2300 INSTALLED including electric connections to break even on the interest ALONE.

It's an expensive green religious icon.

Aside from the eco-fascists obviously in our midst, I like this idea. Have always wanted a wind generator for the science/learning aspect of it.

@Sickness

"one with 5 foot blades and one with 50 foot blades and they both spin at 30RPM they will both generate the exact same power"

Err no they don't, W=FD. If the wind is the same speed on both blades, the 50 foot blade will cover more distance around the outside, therefore more work will be done. Which means torque will be greater on the 50 foot blade around the center than in the 5 foot blade, so it could be geared to make the generator spin faster/not stall when a greater electrical load is put on it.

Increased surface area will also produce more force, therefore requiring less distance (inversely proportional) to do the same work. But when you have more surface area you will introduce more turbulence, and therefore reduce the efficiency of the system. If you want to get the best reliability:work ratio you may as well make large diameter mill since it will produce less noise (the surface area of the blades is spread out over a far greater area therefore it will make less noise per square unit space) and it will not need to run as fast to cover the same distance as a small mill, therefore less wear on the parts and a less complex build.

You need to remember that wind turbines cannot run too fast otherwise they will fail, that is why they generally have big brakes on them or a heavy draw component which will force the windmill to slow down. Some even have variable pitch blades so they can be slowed down to produce the correct power when the wind gets too strong.

Wow. Windmills. Welcome to the 19th century.

Next you'll be telling me to pick up a shovel for those "shovel-ready" jobs. Wouldn't want to use that newfangled hydraulic power. Causes C02, defined by the noted scientists on the Supreme Court as a toxic gas. And they should know....

@w1k1n6: Gosh is that your name or your password? $5494 is about $5000 too expensive for what amounts to a 600 watt generator. Also this is not really a Honeywell product. It is an Earthtronics product that they bought a Honeywell license to rebrand, but Honeywell says in the disclaimer that they make no guarantees about the performance of the product.

@koblog: I see you want to turn this is a climate denial tirade. This has nothing to do with CO2. It's about the fact that we are running out of CHEAP oil. We still have plenty of oil, but it's getting more EXPENSIVE and the basis of our economy is not just oil, it's CHEAP oil. Expensive oil won't help most people. Don't believe me? Then why are we trying to mine tar sands that are several times more expensive than conventional oil? If the oil replenishes itself naturally, as some wishful thinkers on the right would have you believe, why are we building a huge pipeline to bring tar sands into the US? If "drill baby drill" is the answer then forget dirty, expensive tar sands, right? That's like eating garbage out of the dumpster when you could dine in a five star restaurant.

Just to reiterate this issue doesn't have one iota to do with CO2. It has to do with the fact that oil will soon cost several hundred dollars a barrel. Then having a wind generator on your roof might not seem like tree-hugging, granola-munching BS. Just don't buy this one. For a couple hundred dollars you can build one that gives you more power, but only do this if you actually live in a windy place. Otherwise, wind is not the answer for you, but other options do exist for cheap heating, cooling, lighting, etc.

@ aarontco
I see you want to turn this into a climate alarmist tirade with your repeated incorrect usage of the term tarsand. Its oil sand, your dont fractionate gasoline from tar. There is 300 billion barrels of it and it Is produced by a country with a long history of not flying airliners into buildings. Alternative energy is great and more research should be funded but its not ready period. Yes oil is getting much more expensive but it is still a small fraction of the cost of any alternatives we have. Besides the amount of power produced from oil is very small, most of it is coal hydro and nuclear anyways.

lan1108,
Nothing you said was correct. First, I didn't start climate alarmism. I explained, and you failed to understand, "This has nothing to do with CO2". How is that climate alarmism? Answer: *It's not*. You lose point 1. Secondly, this substance is commonly called "tar sand" in the majority of media publications. "Bituminous sands, colloquially known as oil sands or tar sands, are a type of unconventional petroleum deposit." They are called either one. You lose point 2. Your point that Canada has not attacked us 9/11 style is absolutely irrelevant, because those countries, like Saudi Arabia, where the attackers did come from, still sell us good quality oil at cheaper prices. You lose point 3. Alternative energy (it's more accurately called "renewable energy") is very much ready and being used. You even talked about hydro power, which is alternative/renewable, disproving your own claim. You lose point 4. Many other systems such as wind, PV, Solar thermal, geothermal, do produce significant amounts of power, especially elsewhere in the world. Some countries are run almost entirely on renewables, such as Greenland. You really lose point 4. The amount of energy produced from oil is not small, especially for transportation, nor is the absolute size relevant anyway, on matters like transportation. The relevant issue is how convenient oil is for producing gasoline and other products which are very necessary for modern life. Even if oil was "small" that doesn't mean that it cannot be the basis of an economy. Small things can often be strategic. Oil at several hundred dollars a barrel will effectively shut down key elements of our economy, at least as we do them today. Of course we can transition to other things, such as natural gas (see no climate alarmism here). However, none of those things will be without massive expense, nor can they be done overnight. That is why it is important to develop other sources, including wind, which can help us conserve the resources we do have.

Really the media called it tarsands? Well they are always right, you win that point. Saudi Arabia does give us lots of cheap oil so I guess who cares if they funnel money to terrorist groups and treat women like dogs. Ill give you that point too. i think maybe you were talking about Iceland running off of renewables i.e. geothermal which is great for Iceland good for them, plus they gave us Bjork, so they showed us I guess. Your absolutely right about oil powering our transportation, these windmills should charge my Chevy Volt after about 400 years of hurricane force winds, however oil still makes up a very small percentage of electrical production which is whats "relevant" here, so I still kinda win that one. The great thing about your beloved "Tarsands" is that they will prevent oil from going to several hundred dollars an barrel because even though they are more expensive to produce than conventional oil the plants are still profitable at oil priced over 50 dollars a barrel and the excess production they produce will load the supply side of the economic equation. Yes pleaes transition to natural gas, Canada will be happy to sell you that as well but if you dont like expensive energy then you may want to rethink that one. This windmill is a great step forward but Im not selling my high divedend paying oil stocks yet.

Of course they are talking about circumferential speed.
Gee. This should be real easy to build. My ass, rare earth magnets and expensive inverters. Let me get on it and I'll let you know how it went. I guess around 500 bucks will do the trick. Great idea though, using the magnets and coils (induction)on the circumference. The frame from a large industrial fan, some magnets from radar equipment, self spun copper coils.... Just dreaming here.

Yeah ... Even at $5500 (without installation or mounts or connections, etc.) ...
... It has 120V/60Hz output, which is dandy *if* your electric co-op has a "reverse charge" policy and if you are under 12 years old, at time of purchase, so it will pay for it's self, before you die of old age.

Make a "DIY Prosumer" kit version, that puts out DC current, for all us "off-the-grid" types, and I'll give it some real consideration, at ~$1,200 ... Maybe up to ~$2000 USD.

I'll keep looking for it at Wal-Mart ... Perhaps, like most "premium-first-release" products, production will finally scale to the masses and distribution will be competitive.

I'll just take a deep breath, and hold it.

=Blue=

lan1108 needs to rethink the idea that tar sands will prevent oil from going to several hundred dollars a barrel. Their might be huge proven reserves, but there is limited refinery capacity. As conventional oil supplies diminish, possibly rapidly, since the downward slope of Hubbert's Peak may be steeper than the way up, it is doubtful that we will be able to refine tar sands fast enough to make up for the shortfall. Short supply tends to drive up prices.

I agree that natural gas is a good stop gap, but it will also take time. Vehicles can be retrofitted relatively cheaply to run on it, because the cost of replacing hundreds of millions of vehicles with expensive new battery cars would not be trivial. By contrast, many existing automobiles could be modified to run on natural gas for a few hundred dollars.

However, don't lose sight of a few other points. Remember that natural gas *is* used to generate electricity, so having alternate means of electricity production will still be important as the demand for natural gas spikes. Natural gas is also used for heating, as is heating oil. Both can be offset by having alternate means of heating, such as solar and ground or air source heat pumps (which generally also require some electricity to operate, BTW). As I noted, wind might not be the ideal way to generate electricity if you do not live in a windy area. Fortunately there are other means, such as PV, which tend to work even in areas where the sunlight is not intense. Lastly, recall that the only reason I brought up tar sands (though I never made it one word like you consistently do) was as evidence that we are running low on conventional petroleum. That, not CO2, is the more immediate crisis.

The design principle of a shrouded wind turbine with magnets on the blade tips is sound. These designs do produce more power than conventional un-shrouded blade designs because they have no speed increase or reduction gearboxes. Any gearbox will create more friction and that translates to less power and more wind needed to start the turbine from a static resting position, hence less power. The design also allows the blades to turn at much lower wind inputs and makes them less problematic to sudden wind gusts.(A real engineering problem with the large bladed commercial wind farm turbines). The blade tip speed does influence the amount of power generated, but so does the surface area of the pick up coils and the number of "rare-earth" magnets. Why not have a set of fixed (non-moving) stator blades (like a axial flow jet engine compressor) which could increase the area of magnet to coil interaction, and also work to efficiently redirect the air past the second stage of moving blades. Such modifications would increase the cost significantly, but render more than double the output power generated. Alex Ingram

We installed 3 of these turbines and 1 month after the installation, one literally exploded - turns out they forgot to include a key part - the brake for when they go to fast. It took over 4 months to get a replacement turbine and during that time the anemometer on another needed to be replaced... It took 2 months to get a replacement part. A few months later the bearings went out on one! Windtronics will not even return our phone calls. The product and the service are a disgrace - even if they could produce the energy they promise...

Wow.

Read a lot of the points no wonder Honeywell Axed this product. It was neat idea but very poor execution.

Also everyone forgets Taxes on power, delivery fee, and in some cases local taxes. If you use ZERO power in a month you get a bill of at least $30. So add $400 to $800 in extra fees a year. So if you off grid the payback could be 10.

Also in many countries the Government will pay up to 90% and in most cases 50% of the turbine . So in some places (ie California etc) Power 25 cents a kW $360 power save this year, plus $5000 grant to install a turbine and Fed tax incentive $1250 a year. Your first year saving COULD BE $1610 and it cost you $5000.

In other places the government pays more for environment power (ie Ontario Canada buys at 18 cents and sells for 10 cents, Montana does the same sort of thing.) So in good place the pay back could be under 3 years.