Design

Published on January 16th, 2009 | by Low Impact Living

7

A Wind Turbine for Every Rooftop?

WindspireThese days, there are more and more options for those of you who want a small wind turbine out in the yard or on your roof. They range from the standard to the somewhat bizarre, and come in sizes that can power several major appliances all the way up to your whole house and beyond. In the right conditions, wind power can be much more economical than other renewable energy options such as solar or geothermal.

Traditional propeller-type wind turbines remain the best options for residential settings outside of urban areas. They are efficient and time-tested, and the leading manufacturers of these turbines have been at it for a long time. Two of the leaders are Bergey Windpower and Southwest Windpower. Bergey makes several versions of its Excel turbine suitable for home use. The Excel can be connected to the electrical grid and is big enough to power an entire home.

skystream at capitol

Southwest Windpower makes the Skystream 3.7 turbine (shown at left), an innovative machine that has a number of advances specifically targeted to residential users. It is meant to be tied to the electricity grid, and in reasonably windy conditions could power an average home.

In the past few years, a number of new manufacturers have come out with radical turbine designs intended to make wind turbines easier to install and better for tightly packed suburban and urban environments. Most of these turbines are vertical axis wind turbines, or VAWTs. Instead of spinning on a horizontal axis like their propeller-based cousins, VAWTs rotate around a vertical axis. The key advantages are that they can be quieter, are more amenable to the swirling wind conditions found in urban environments, and can have a smaller overall footprint (both tower width and height). The downsides? The companies that make them don’t have long track records, and the turbines are less efficient because a portion of each turbine is always spinning into the wind.

One example is Mariah Power, who makes the Windspire wind turbine (shown in the upper right image above). Each Windspire turbine is 30 feet tall and two feet wide, and it resembles a sculpture as much as it does a renewable energy device. The cylindrical structure makes it very quiet and compact, meaning you could install multiple turbines alongside one another for more power. Each unit should provide from 10-50% of the electricity for a typical home depending on where you live in the country.

Another example is Helix Wind. The company make several vertical axis turbines that, in my opinion, most closely resemble a ram’s horn. The complex (and weird or beautiful, depending on your sensibilities) design efficiently transforms variable winds into clean electricity. Their largest model, the S594, can provide 50-100% of a typical home’s electricity use under the right conditions.

So, now that you’re intrigued, should you run out and buy a new wind turbine for your rooftop or back yard?

Not so fast – there are some major caveats with wind power. The first is pretty self-explanatory - you need quite a bit of wind. Ideally it should be windier more often than not, and the harder the better. The energy that wind turbines generate is proportional to the cube of wind speed, which means that a wind turbine in 20 mph of wind will generate EIGHT times as much energy as the same turbine in 10 mph of wind (all other factors being equal). Ideal spots for wind power are coastal areas with steady sea breezes, or open expanses such as the Great Plains where winds really howl.

Skystream GuidanceSecond, the turbine should be as high as possible and well away from any obstructions. We’ve seen many Photoshop images or illustrations of wind turbines on rooftops in urban areas, but the truth is that there’s just more wind the higher you get off the ground or rooftop. As an example, the wind speed at 50 feet above ground will be about 25% faster than the wind speed at 60 feet. That’s great if you’re on the 90th floor of a skyscraper, but not if you own a one-story home in a typical neighborhood. The buildings, structures and trees in urban areas play havoc with wind speeds and directions. That wind turbine happily spinning five feet above your garage might look good, but it will perform much better (2x better or more) if it’s 50 feet higher. And payback period is all about performance. Typical guidelines for horizontal turbines are that the bottom of your turbine should be 3x above the nearest upwind barrier, or 25 feet above any upwind obstacles within 300-500 feet (whichever is higher).

Third, getting the required permits and approvals to install a wind turbine can be thorny. There are a number of issues with wind turbines that you don’t have to face with solar panels. There’s a perceived noise issue, although testing of modern turbines doesn’t support this negative. There can be an impact on views, especially if you’ve elevated your turbine into the proper wind zones. Some people and jurisdictions are worried about safety should a turbine fall, but the American Wind Energy Assocation states that there haven’t been any injuries from falling turbines in 25 years. And, there’s a concern about the impact of turbines on birds and wildlife. This is a major issue for utility-scale turbines, but the National Audubon Society in California found that small wind turbines pose little or no additional risk to our feathered friends. The net result of all of this is that depending on where you live, you’ll have to go through a somewhat complicated permitting process. A good installer can help navigate the process, so choose wisely! (we have a number of good wind energy installers in our service providers directory.)

We hope that the technology, zoning laws and financial incentives all improve to the point that small wind turbines are a common sight on our skylines. Until then, we applaud those urban wind pioneers among you who are willing to overcome the challenges of small wind. Should you choose that path, here are some additional resources that talk about the challenges and how to manage them:




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  • TJ

    Unlike the traditional propeller type windmills, the vertical windmills will work fine at the roof level of most homes and lower wind speeds. This should make it easier to argue for a permit since it does not need such a tall tower.

    I did see the propeller windmill near the capitol building a few months ago. It was on a small tower, and I could not hear a sound coming from it. If you can, take a drive to DC to see it.

    I think once the newer household windmills propagate and more people see, hear, and experience them first hand, the special interest groups will with their spreading of disinformation about them will lose. Know the truth and the truth will set you free.

  • TJ

    Unlike the traditional propeller type windmills, the vertical windmills will work fine at the roof level of most homes and lower wind speeds. This should make it easier to argue for a permit since it does not need such a tall tower.

    I did see the propeller windmill near the capitol building a few months ago. It was on a small tower, and I could not hear a sound coming from it. If you can, take a drive to DC to see it.

    I think once the newer household windmills propagate and more people see, hear, and experience them first hand, the special interest groups will with their spreading of disinformation about them will lose. Know the truth and the truth will set you free.

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  • Lawrence Baker

    The Baker Wind Turbine is a major breakthrough in wind energy technology. The super quiet, Low Pressure Turbine is enclosed and 100% bird and people safe which allows the turbine to be installed and operated in close proximity to people. This eliminates the need for long transmission lines because the electricity is consumed close to where the electricity is generated. The 12 feet in diameter Model #3 Baker Wind Turbine is mounted on a car trailer and the unit is easily transported. Set-up is easy. The outriggers lift the turbine foundation and stabilize the turbine so that it can rotate 360 degrees. The fenders and tires are removed. No tower is needed; all that is necessary is a 6’ by 6’ wind flow. More efficient and powerful than a single dimension propeller driven windmill, this multidimensional wind energy turbine dynamic has never been seen before. Of course, the multidimensional turbine dynamic does not even resemble a single dimension propeller driven windmill. Google Baker Wind Turbine and two videos will appear; the longer video demonstrates the Low Pressure Turbine Dynamic.
    Let me explain to you the basic turnaround in wind energy science and technology demonstrated by the Baker Wind Turbine. You don’t have to be a genius to understand wind energy.
    First, the maximum amount of energy in the wind is directly in front of the wind. This is the basic and simple premise and is easily proven to anyone logically. (Aristotelian logic is the foundation of all science.) While standing in the wind, face the full force of the wind which is directly in front of the wind. Now, form both hands into a cup which represents a ½ round, cupped turbine vane with volume. Now, cross over your hands and form a blade with no volume representing a propeller driven wind mill. Which of the two forms catch more wind and has full thrust from the wind?
    The first part of the equation is solved: The maximum amount of energy in the wind is directly in front of the wind and the best surface form to catch the wind and consequently, has more thrust and power, is a ½ round aluminum turbine vane with volume.
    The second part of the equation is as logical. Which direction will the maximum wind catch area turbine vane turn? Naturally, the turbine vanes and rotor turn harmoniously in the same direction as the wind is blowing. This eliminates wind noise caused by turbulence. A propeller blade rotates sideways to the wind energy airstream which results in less power produced, noise from propeller turbulence and high stress on bearings and blades creating high maintenance cost. Propellers are so big; birds can’t see them and they have devastated wild bird populations. Check out the out of control wind propeller explosions on You Tube.
    The third part of the equation is that the more cupped wind catch surface area that is directly in front of the wind, the more powerful the turbine. A single dimension propeller can only expand in size and power by increasing its’ diameter. The multidimensional Baker Wind Turbine can not only increase its’ power by increasing its’ diameter but can expand horizontally and add exponentially more wind catch surface area and power.
    The Baker Wind Turbine has 144 cupped turbine vanes that are 3 inches wide (5 ½ inches of surface area). The 3 inch aluminum vanes give us 11 inches of weld at the cupped base. Each turbine vane has 1 1/2 sq. ft. of cupped surface area. This is important because the stress per catch area unit is low as apposed to a large catch area with a high stress attachment to the hub. No one turbine vane pulls by itself but pulls together with the other turbine vanes in a “gang”. This spreading of wind energy over the rotor maximizes the wind catch area and spins the rotor smoothly without vibration. Each turbine hub has 6 turbine vanes that are 6 ft. long. There are 24 hubs (6ft. wide) and there are 18 rows. Each row has 8 members that contain 48 lineal ft. of turbine vanes. At any given moment, the top section contains 108 sq. ft. of cupped wind catch surface area. As each row is assembled, they are progressively stepped which forms a horizontal twist. Twist is torque and torque is horsepower. The more twist, the more horsepower. Dividing the diameter into 18 lateral rows creates massive torque that is visible. For example take a wood screw and hold it sideways and turn it. You will notice that the screw is made up of one helix and 8 or more twists (or flights). The Baker Wind Turbine is Like the Archimedean screw but made up of 6 helixes with 8 twists which torque from right to left six feet. The overall dynamic of the Baker Wind Turbine is germane to High Pressure Turbine Dynamics but adapted to Low Pressure Turbine Dynamics which I am the inventor of and the Baker Wind Turbine is the test prototype. Just as Mr. Parsons’ invention of the high pressure steam turbine revolutionized steam power; the Baker Wind Turbine will revolutionize low pressure wind power.
    The Baker Wind Turbine rotor has a lower surface to weight ratio than a propeller windmill so the rotor and shaft which weigh 660 lbs. begins turning on 1 or 2 miles an hour of wind and will operate smoothly and quietly in a 100 mile an hour wind at an estimated (920 R.P.M). High pressure steam and gas turbines operate at 20,000 to 50,000 R.P.M or higher; so in high winds the low pressure turbine dynamic is figuratively just loafing along. The Baker Wind Turbine not only has a wider range of operation but also produces more power at any given wind speed than a propeller driven wind mill and therefore the new turbine wind energy technology should rightfully outmode the old propeller driven windmill technology. The Baker Wind Turbine, like all major inventions, has a wide range of applications that will change roof top architecture, bridge design, ship design, high speed train (forced air) electric grid locomotives, forced air/ electric cars, parks, backyards, airports and all areas where the wind can be utilized in a natural or forced air environment. The turbine is enclosed so the housing can be easily painted to blend in with the surrounding area.
    The last part of the equation is a little harder to grasp, even some engineers don’t get it straight. Those who defy convention and who can think individually in multidimensional terms get it right away.
    First the single dimension. One assumption in Betz’ Law is that a solid wall is considered 100 % efficient in the wind and a propeller is considered 50% efficient because half of the wind flows through the propeller which causes the propeller to turn. So, 6 feet by 6 feet swath of airstream at, lets say, 10 pounds pressure per square foot (pounds is air speed and density) would give you 360 pounds of pressure thrust overall. A 50% efficient propeller would have 180 lbs. of thrust available. A three blade propeller with 5 ½ inch wide blades and 6 foot in diameter (4 1/2 sq. ft. surface area or 40.5 lbs thrust) produces but a fraction of one horsepower. The reason for this is a small surface area propeller rotates on a flat plane sideways to the energy source, has little torque, and is of a single dimension.
    The multidimensional Baker Wind Turbine wind in-take is 6 feet high by 6 feet wide by 12 feet deep. The wind travels laterally across the turbine top section 12 feet to the other side which creates rotary power. The turbine rotor vanes are denser close to the center of the hub and wider at the tips and spaced such that the wind passes through the turbine to the other side. Again, hold up the wood screw. Notice by looking across the top half of the screw that there are air passages to the other side? Remember the Baker Wind Turbine has 6 helixes and 8 twists and the air passages move from right to left six feet? Now, look at the down wind side of the screw and you will notice that the flight is open and fanned out and is not drafted by the spiral? The turbine spirals leading edge is made up of many turbine vanes from many different rows so they do not draft one another. Of course, the leading edge of the opening is constantly changing as the rotor turns. At the apex of the turbine, as observed directly in front of the wind in-feed, the vanes form a continuous wall dimensionally. Because there are dimensional openings between the turbine vanes, and air is highly fluid, the wind powers all nine rows at any given moment from one side to the other. Each row is one dimension under wind power and there are 9 rows. There are 48 lineal feet of 3 inch cupped turbine vanes per row and 108 cupped sq. ft. total under power. If we figure out our total surface area in the top section it would contain 198 sq. ft. of surface area under wind power. At 10 pounds per sq. ft. that would be 1,980 pounds of thrust overall. That is 49 times more than the estimated efficiency of 40.5 pounds thrust for a single dimension propeller operating in the same 6 feet by 6 feet airstream! The Baker Wind Turbine is even more powerful than just converting speed and density of air into rotary power, the traveling torque creates even more horsepower, however, digging into traveling torque equations at this time is not necessary. My point has already been proven in science that Baker Low Pressure Turbine Dynamics is at least 49 times more powerful then a propeller driven wind mill dynamic and my 12 feet in diameter low pressure turbine proves it. That is why I built model #3 so that people could see the powerful turbine dynamic operate even though they do not understand how it works or all of the ramifications of it working. Now you know how it works and basically the breakthrough technology of Baker Low Pressure Turbine Dynamics. Did you get it? Or was it to much for your wee mind? For those who get it, read on. For those who don’t get it; drive down the road at 65 mph. and cup your hand into the wind and let it jerk your arm back (lever) and each time ask yourself “where is the power and energy in the wind”?
    The reason the modern American Green Energy Economy is not moving forward is because independent scientist and individual inventors, like me, are without funding. The reason there is no funding is because the economic powers that be, the status quo, has snuffed any State or Federal funding programs for independent green energy inventors. Are you surprised there is no level ground? Do you know what scares the hell out of the multinational Big Oil and energy barons? The answer is the advancement of science with new inventions that they can’t control (their economy) that would outmode the use of fossil fuels for energy (their product). That is the cause of man made Global Warming.
    Logically, one would think that the first government action would be to utilize our national talent by holding a national green energy science contest thereby acting free from Big Oil. I am not the only independent inventor; there would be thousands of qualified applicants with new concepts. The winner would receive a one million dollar reward to further develop the new green energy concept. Ten million a month could finance and develop ten new grass root industries employing thousands in green energy jobs. Out with the old and in with the new, let the best win in science and the lesser fold or be outmoded by something even better. That is fair competition and free enterprise. A modern American Main Street Capitalism based on a green energy economy would grow from the bottom up and not be dominated and controlled by multinational corporations from the top down. Great inventors were individuals not controlled universities; they should be funded as well.
    Lawrence Baker
    650-218-9434 windcatch@gmail.com

  • Lawrence Baker

    The Baker Wind Turbine is a major breakthrough in wind energy technology. The super quiet, Low Pressure Turbine is enclosed and 100% bird and people safe which allows the turbine to be installed and operated in close proximity to people. This eliminates the need for long transmission lines because the electricity is consumed close to where the electricity is generated. The 12 feet in diameter Model #3 Baker Wind Turbine is mounted on a car trailer and the unit is easily transported. Set-up is easy. The outriggers lift the turbine foundation and stabilize the turbine so that it can rotate 360 degrees. The fenders and tires are removed. No tower is needed; all that is necessary is a 6’ by 6’ wind flow. More efficient and powerful than a single dimension propeller driven windmill, this multidimensional wind energy turbine dynamic has never been seen before. Of course, the multidimensional turbine dynamic does not even resemble a single dimension propeller driven windmill. Google Baker Wind Turbine and two videos will appear; the longer video demonstrates the Low Pressure Turbine Dynamic.
    Let me explain to you the basic turnaround in wind energy science and technology demonstrated by the Baker Wind Turbine. You don’t have to be a genius to understand wind energy.
    First, the maximum amount of energy in the wind is directly in front of the wind. This is the basic and simple premise and is easily proven to anyone logically. (Aristotelian logic is the foundation of all science.) While standing in the wind, face the full force of the wind which is directly in front of the wind. Now, form both hands into a cup which represents a ½ round, cupped turbine vane with volume. Now, cross over your hands and form a blade with no volume representing a propeller driven wind mill. Which of the two forms catch more wind and has full thrust from the wind?
    The first part of the equation is solved: The maximum amount of energy in the wind is directly in front of the wind and the best surface form to catch the wind and consequently, has more thrust and power, is a ½ round aluminum turbine vane with volume.
    The second part of the equation is as logical. Which direction will the maximum wind catch area turbine vane turn? Naturally, the turbine vanes and rotor turn harmoniously in the same direction as the wind is blowing. This eliminates wind noise caused by turbulence. A propeller blade rotates sideways to the wind energy airstream which results in less power produced, noise from propeller turbulence and high stress on bearings and blades creating high maintenance cost. Propellers are so big; birds can’t see them and they have devastated wild bird populations. Check out the out of control wind propeller explosions on You Tube.
    The third part of the equation is that the more cupped wind catch surface area that is directly in front of the wind, the more powerful the turbine. A single dimension propeller can only expand in size and power by increasing its’ diameter. The multidimensional Baker Wind Turbine can not only increase its’ power by increasing its’ diameter but can expand horizontally and add exponentially more wind catch surface area and power.
    The Baker Wind Turbine has 144 cupped turbine vanes that are 3 inches wide (5 ½ inches of surface area). The 3 inch aluminum vanes give us 11 inches of weld at the cupped base. Each turbine vane has 1 1/2 sq. ft. of cupped surface area. This is important because the stress per catch area unit is low as apposed to a large catch area with a high stress attachment to the hub. No one turbine vane pulls by itself but pulls together with the other turbine vanes in a “gang”. This spreading of wind energy over the rotor maximizes the wind catch area and spins the rotor smoothly without vibration. Each turbine hub has 6 turbine vanes that are 6 ft. long. There are 24 hubs (6ft. wide) and there are 18 rows. Each row has 8 members that contain 48 lineal ft. of turbine vanes. At any given moment, the top section contains 108 sq. ft. of cupped wind catch surface area. As each row is assembled, they are progressively stepped which forms a horizontal twist. Twist is torque and torque is horsepower. The more twist, the more horsepower. Dividing the diameter into 18 lateral rows creates massive torque that is visible. For example take a wood screw and hold it sideways and turn it. You will notice that the screw is made up of one helix and 8 or more twists (or flights). The Baker Wind Turbine is Like the Archimedean screw but made up of 6 helixes with 8 twists which torque from right to left six feet. The overall dynamic of the Baker Wind Turbine is germane to High Pressure Turbine Dynamics but adapted to Low Pressure Turbine Dynamics which I am the inventor of and the Baker Wind Turbine is the test prototype. Just as Mr. Parsons’ invention of the high pressure steam turbine revolutionized steam power; the Baker Wind Turbine will revolutionize low pressure wind power.
    The Baker Wind Turbine rotor has a lower surface to weight ratio than a propeller windmill so the rotor and shaft which weigh 660 lbs. begins turning on 1 or 2 miles an hour of wind and will operate smoothly and quietly in a 100 mile an hour wind at an estimated (920 R.P.M). High pressure steam and gas turbines operate at 20,000 to 50,000 R.P.M or higher; so in high winds the low pressure turbine dynamic is figuratively just loafing along. The Baker Wind Turbine not only has a wider range of operation but also produces more power at any given wind speed than a propeller driven wind mill and therefore the new turbine wind energy technology should rightfully outmode the old propeller driven windmill technology. The Baker Wind Turbine, like all major inventions, has a wide range of applications that will change roof top architecture, bridge design, ship design, high speed train (forced air) electric grid locomotives, forced air/ electric cars, parks, backyards, airports and all areas where the wind can be utilized in a natural or forced air environment. The turbine is enclosed so the housing can be easily painted to blend in with the surrounding area.
    The last part of the equation is a little harder to grasp, even some engineers don’t get it straight. Those who defy convention and who can think individually in multidimensional terms get it right away.
    First the single dimension. One assumption in Betz’ Law is that a solid wall is considered 100 % efficient in the wind and a propeller is considered 50% efficient because half of the wind flows through the propeller which causes the propeller to turn. So, 6 feet by 6 feet swath of airstream at, lets say, 10 pounds pressure per square foot (pounds is air speed and density) would give you 360 pounds of pressure thrust overall. A 50% efficient propeller would have 180 lbs. of thrust available. A three blade propeller with 5 ½ inch wide blades and 6 foot in diameter (4 1/2 sq. ft. surface area or 40.5 lbs thrust) produces but a fraction of one horsepower. The reason for this is a small surface area propeller rotates on a flat plane sideways to the energy source, has little torque, and is of a single dimension.
    The multidimensional Baker Wind Turbine wind in-take is 6 feet high by 6 feet wide by 12 feet deep. The wind travels laterally across the turbine top section 12 feet to the other side which creates rotary power. The turbine rotor vanes are denser close to the center of the hub and wider at the tips and spaced such that the wind passes through the turbine to the other side. Again, hold up the wood screw. Notice by looking across the top half of the screw that there are air passages to the other side? Remember the Baker Wind Turbine has 6 helixes and 8 twists and the air passages move from right to left six feet? Now, look at the down wind side of the screw and you will notice that the flight is open and fanned out and is not drafted by the spiral? The turbine spirals leading edge is made up of many turbine vanes from many different rows so they do not draft one another. Of course, the leading edge of the opening is constantly changing as the rotor turns. At the apex of the turbine, as observed directly in front of the wind in-feed, the vanes form a continuous wall dimensionally. Because there are dimensional openings between the turbine vanes, and air is highly fluid, the wind powers all nine rows at any given moment from one side to the other. Each row is one dimension under wind power and there are 9 rows. There are 48 lineal feet of 3 inch cupped turbine vanes per row and 108 cupped sq. ft. total under power. If we figure out our total surface area in the top section it would contain 198 sq. ft. of surface area under wind power. At 10 pounds per sq. ft. that would be 1,980 pounds of thrust overall. That is 49 times more than the estimated efficiency of 40.5 pounds thrust for a single dimension propeller operating in the same 6 feet by 6 feet airstream! The Baker Wind Turbine is even more powerful than just converting speed and density of air into rotary power, the traveling torque creates even more horsepower, however, digging into traveling torque equations at this time is not necessary. My point has already been proven in science that Baker Low Pressure Turbine Dynamics is at least 49 times more powerful then a propeller driven wind mill dynamic and my 12 feet in diameter low pressure turbine proves it. That is why I built model #3 so that people could see the powerful turbine dynamic operate even though they do not understand how it works or all of the ramifications of it working. Now you know how it works and basically the breakthrough technology of Baker Low Pressure Turbine Dynamics. Did you get it? Or was it to much for your wee mind? For those who get it, read on. For those who don’t get it; drive down the road at 65 mph. and cup your hand into the wind and let it jerk your arm back (lever) and each time ask yourself “where is the power and energy in the wind”?
    The reason the modern American Green Energy Economy is not moving forward is because independent scientist and individual inventors, like me, are without funding. The reason there is no funding is because the economic powers that be, the status quo, has snuffed any State or Federal funding programs for independent green energy inventors. Are you surprised there is no level ground? Do you know what scares the hell out of the multinational Big Oil and energy barons? The answer is the advancement of science with new inventions that they can’t control (their economy) that would outmode the use of fossil fuels for energy (their product). That is the cause of man made Global Warming.
    Logically, one would think that the first government action would be to utilize our national talent by holding a national green energy science contest thereby acting free from Big Oil. I am not the only independent inventor; there would be thousands of qualified applicants with new concepts. The winner would receive a one million dollar reward to further develop the new green energy concept. Ten million a month could finance and develop ten new grass root industries employing thousands in green energy jobs. Out with the old and in with the new, let the best win in science and the lesser fold or be outmoded by something even better. That is fair competition and free enterprise. A modern American Main Street Capitalism based on a green energy economy would grow from the bottom up and not be dominated and controlled by multinational corporations from the top down. Great inventors were individuals not controlled universities; they should be funded as well.
    Lawrence Baker
    650-218-9434 windcatch@gmail.com

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