Article Code: S-14
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Wind Energy Technology
Wind Turbines Classification
Old & Future Designs of Wind Turbine
Global Markets & Economics of Wind Energy Technology
Environmental Impacts of Wind Technology
Techniques for Increasing the Wind Power
New Designs of Wind Turbines
Citations (References & Websites)
Today, electricity is considered as the nerve system for many advanced countries. Nobody may doubt, that fossil fuels & coal has made a significant & positive impacts in the beginning of the industrial revolution after 1881 until today for the people in many different aspects of life (welfare, creating jobs, commerce & communication). But the ignorance of negative effects of fossil fuel & coal towards beautiful environment was horrible & not expected in the long term. (with the exclusive use of it as a source for supplying electricity needs for contemporary societies).
Changing the weather patterns, global warming, rising the sea level, more drought, hurricanes & rainfall in specific areas & melting the ice of arctic & Antarctic zones All this terrible actions may be named as “Climate Change’.
For mitigation the catastrophes by climate change actions & global warming effects, many scientists & activists of environmental & climate fields called governments & companies to deploy the renewable energies (e.g. solar, wind, hydro-power, geothermal, bio-fuels & tidal of seawater), as it is clean (can’t produce GHGs & pollute the atmosphere ) & it’s renewable source of energy. In other term, it’s named as “Green Power”.
Renewable energies/Green Power technologies has been applied widespread in many countries compared to the previous decades. Although, it has a great & positive on social, economical & environmental impacts, it still ( renewable energy technologies ) can’t be fully relied upon, as it encountered some challenges & Obstacles to achieve higher & excellent rate of performance.
Low of energy density, high initial cost & lower energy efficiency of some technologies (solar & wind) are the main factors which prevent us to utilize 100% from renewable sources.
In this scientific article we will talk about wind energy in general as it’s considered as growing industry & promising future technology if we solve its recent challenges related to increase the power.
We will mention different types of wind turbines & the innovative futuristic concepts (airborne wind turbine). Then will discuss some ways to improve the power of wind turbine by using some creative methods which may reduce the initial cost of investment. In the end we will introduce 5 new designs of wind turbines which is differ totally from the traditional wind turbine in the global market.
Wind Energy Technology:
Figure (1) – Wind in Nature
Wind is natural phenomenon in earth which is been created by the difference of air density. It’s in simple words “an atmospheric air in motion”.
The cold air is more dense than hot air, then the cold air will move from the upper to bottom layers of earth & the hot air will move to upper layers. In another hand, wind has been formed by pressure difference of zones. Low pressure will rise & high pressure will sink. Figure (2) shows this process of temperature difference for creation wind.
Figure (2) – Mechanism of Wind Motion
ir with high temperature has low pressure compared to the low temperature. Then, the hot air will rise.
You may read more about wind in my scientific article “El-Nino Phenomenon : Possibility of Human Controlling” here [Link]
There are spatial scales of wind such as [Ref-1]:
- Planetary Scale: global circulation
- Synoptic Scale: weather systems
- Meso-Scale: local topographic or thermally induced circulations
- Micro Scale: urban topography
There are many types of wind motion, like;
• Planetary circulations:
– Jet stream
– Trade winds
– Polar jets
• Geo-strophic winds.
• Thermal winds.
• Gradient winds.
• Katabatic/Anabatic winds – topographic winds.
• Bora / Foehn / Chinook – down-slope wind storms.
• Sea Breeze / Land Breeze.
• Convective storms / Downdrafts.
• Hurricanes/ Typhoons.
• Gusts / Dust devils / Micro-bursts.
• Nocturnal Jets.
• Atmospheric Waves.
Figures from (3) to (7) shows some of these different types of wind in earth.
Figure (3) – Hurricanes
Figure (4) – Hurricanes in Land
Figure (5) – Large Tornadoes
Figure (6) – Tornadoes
Figure (7) – Dust Devils & Convective Storms
Utilizing from the wind motion is not a new idea. It has been used as long as humans have put sails into the wind. For more than two millennia wind-powered machines have ground grain and pumped water.
Figure (8)- Charles Brush’s windmill of 1888, used for generating electric power
Figure (9) – Wind Mills
Wind power was widely available and not confined to the banks of fast-flowing streams, or later, requiring sources of fuel. Wind-powered pumps drained the polders of the Netherlands, and in arid regions such as the American mid-west or the Australian outback, wind pumps provided water for live stock and steam engines. [Web-1]
Wind is plentiful, cleaner, no consumes water or fuel & required little area of land. It’s flexible technology as it may be installed either onshore or offshore.
The Power of Wind
Any motion of wind means it has a available kinetic energy which is governed by the equation :
ρ: The density of air.(Kg/m3)
A: the area of air stream. (m2)
v: Speed of air stream. (m/s)
Kinetic energy of wind is converted to mechanical (rotational) energy by using a wind turbine blades.
The percentage of extracted power of kinetic energy (input) to mechanical energy (output) is named as ‘Turbine Power Coefficient/efficiency” & its equation:
Cp :Turbine power coefficient/efficiency.
Then, by substituting equation (1) of wind power in equation (2), we will find that ;
The last equation is represent the mechanical power of turbine (output). Then, the shaft of rotor will convert the mechanical energy to electric energy by using electric generator.
The multi units of wind turbines in specific location called a “Wind Farm” which is connected to each other to the electric power transmission network (grid) of the country. Figure (10) shows the green mountain energy wind farm at Brazos which is located in Fluvanna in Texas, USA in 2004.
Figure (10) – Brazos Wind Farm in Texas, USA
Onshore wind is an inexpensive source of electric power, competitive with or in many places cheaper than coal or gas plants. Offshore wind is steadier and stronger than on land, and offshore farms have less visual impact, but construction and maintenance costs are considerably higher.
Small onshore wind farms can feed some energy into the grid or provide electric power to isolated off-grid locations. [Web-1]
There are two important notes about wind turbine;
Firstly, The temperature of air (gas) has a direct relationship with density of air according to the ideal gas law:
P: The pressure of air (KPa)
ρ: The density of air.(Kg/m3)
T: absolute temperature (Kelvin “K”)
R: Gas constant (KJ/Kg.K)
So, increasing the temperature, will lead to decrease the density. This will effect on the reduction of output power of wind turbine as it has a direct proportional with density. So, we note that temperature has an inverse proportional relationship with wind power.
Secondly, the maximum theoretical power coefficient/efficiency (Cp) = 59.3%. Its named as “Betz’s law/limit” (1919). The wind turbine blade efficiency is maximum when it slows the wind to one-third of its original velocity. Modern wind turbine blades can approach 80 percent of the Betz’s limit, ( i.e., 45% – 50% efficiency in converting the power in the wind into the power of a rotating generator shaft). [Ref-2 ]
Offshore Wind Energy Technology
Figure (11 ) – Wind Float Prototype in Agucadoura, Portugal
Offshore wind farms are an exciting new area for the industry, largely due to the fact that there are higher wind speeds available offshore and economies of scale allow for the installation of larger size wind turbines offshore.
Offshore wind turbine technology is based on the same principles as onshore technology.
Foundations are constructed to hold the superstructure, of which there are a number of designs, but the most common is a driven pile. The top of the foundation is painted a bright color to make it visible to ships and has an access platform to allow maintenance teams to dock. Subsea cables take the power to a transformer, (which can be either offshore or onshore) which converts the electricity to a high voltage (normally between 33 kV and 132 kv) before connecting to the grid at a substation on land. [Ref -3 ]
Today’s offshore turbines range from 3 MW to 5 MW in size and typically have three-blades, operate with a horizontal-axis upwind rotor, and are nominally 80 to 126 m in diameter. Tower heights offshore are lower than land-based turbines because wind shear profiles are less steep, tempering the energy capture gains sought with increased elevation. The offshore foundations differ substantially from land-based turbines.
The baseline offshore technology is deployed in arrays using mono-piles at water depths of about 20 m. Mono-piles are large steel tubes with a wall thickness of up to 60 mm and a diameter of 6 m. The embedment depth will vary with soil type, but a typical North Sea installation will require a pile that is embedded 25 to 30 m below the mud line that extends above the surface to a transition piece with a leveled and grouted flange on which the tower is fastened. Mobilization of the infrastructure and logistical support for a large offshore wind farm is a significant portion of the system cost. [Ref -4]
Figure (12) – Evolution of US Commercial Wind Technology
Current estimates indicate that the cost of energy from offshore wind plants is above 0.10 $/kWh and that the O&M (operation & maintenance) costs are also higher than for land-based turbines due to the difficulty of accessing turbines during storm conditions. [Ref -4 ]
Figures from (13) to (16) shows the construction of offshore wind turbines.
The types of offshore wind turbine foundations is depend on the depth of the seawater. Figure (17) shows the design of it for various depth of seawater.
Figure (17) – The Development of Offshore Wind Turbines
Wind Turbines Classification:
Figure (18) – Wind Power Plants in Xinjiang, China
Famous Wind turbines are subdivided into two general groups:
- Horizontal Axis Wind Turbine (HAWT).
- Vertical Axis Wind Turbine (VAWT).
A horizontal axis machine has its blades rotating on an axis parallel to the ground. A vertical axis machine has its blades rotating on an axis perpendicular to the ground. There are a number of available designs for both and each type has certain advantages and disadvantages. However, compared with the horizontal axis type, very few vertical axis machines are available commercially.
Figure (19) – HAWT & VAWT Types
Although vertical axis wind turbines have existed for centuries, they are not as common as their horizontal counterparts. The main reason for this is that they do not take advantage of the higher wind speeds at higher elevations above the ground as well as horizontal axis turbines. [Ref-5]
Horizontal axis wind turbines (HAWT) are the most popular – compared to vertical axis wind turbines (VAWT).
Advantages of VAWT:
(a) automatically faces the wind,
(b) the heavy machinery can be located on the ground,
(c) light weight.
Disadvantages of VAWT:
(a) the blades are close to the ground (low speed, turbulent wind),
(b) hard to spill the wind.
Note: Advantages & disadvantages has been found in reference 2. [Ref-2]
How does blades of wind turbine work ?
There are two types for operating wind turbines:
- Drag type.
- Lift type (Pressure difference).
Airflow over any surface creates two types of aerodynamic forces – drag forces, in the direction of the airflow, and lift forces, perpendicular to the airflow. Either or both of these can be used to generate the forces needed to rotate the blades of a wind turbine.[Web-2].
Figure (20) shows the drag & lift force in wing & how the attack angle affect on determine either lift or drag force is prevail in specific application. Stall will appear when the attack angle increase.
Figure (20) – Lift & Drag Force
Drag – Based Wind Turbine:
In drag-based wind turbines, the force of the wind pushes against a surface, like an open sail. In fact, the earliest wind turbines, dating back to ancient Persia, used this approach. The Savonius rotor is simple drag-based windmill that you can make at home. It works because the drag of the open, or concave, face of the cylinder is greater than the drag on the closed or convex section.
Figure (21) – Savonius Wind Turbine
Lift – Based Wind Turbine:
The rotor blades extract energy from the wind based on Bernoulli’s principle to obtain lift (i.e., due to pressure difference & this principle used in plane wings ).
More energy can be extracted from wing using lift rather than drag, but this requires specially shaped airfoil surfaces, like those used on airplane wings. The airfoil shape is designed to create a differential pressure between the upper & lower surfaces, leading to a net force in the direction perpendicular to the wind direction.
Rotors of this type must be carefully oriented (the orientation is referred to as the rotor pitch), to maintain their ability to harness the power of the wind as wind speed changes.
Figure (22) – Lift Force due to pressure difference in Plane
Since the blade is moving much faster at the tip than near the hub, the blade must be twisted along its length to keep the angles right. Increasing the angle of attack too much can result in a stall. When a wing stalls, the airflow over the top no longer sticks to the surface and the resulting turbulence destroys lift. [Ref-2]
Although most of the largest wind turbines now employ active pitch control, in the recent history of wind turbine technology, the use of aerodynamic stall to limit power has been a unique feature of the technology.
Most aerodynamic devices (aero-planes and gas turbines, for example) avoid stall. Stall, from a functional standpoint, is the breakdown of the normally powerful lifting force when the angle of flow over an aero-foil (such as a wing section) becomes too steep. This is a potentially fatal event for a flying machine, whereas wind turbines can make purposeful use of stall as a means of limiting power and loads in high wind speeds. [Ref-6]
Optimal Number of blades
If more than 3 blades, the turbulence caused by one blade affects the efficiency of the blade that follows. If less than 3 blades, power and torque pulsations will appear at the generator terminals. Three-bladed turbines show smoother and quieter operation, with minimum aerodynamic interference.
Components of Wind Turbine
Regardless of the type of wind turbines, it contains some main components which they are:
- Tower: Usually manufactured in sections from rolled steel; a lattice structure or concrete are cheaper options.
- Rotor Blades: Manufactured in specially designed moulds from composite materials, usually a combination of glass fiber & epoxy resin. Options include polyester instead of epoxy and the addition of carbon fiber to add strength & stiffness.
- Rotor Hub: Made from cast ion.
- Rotor Bearings.
- Main Shaft: Transfers the rotational force of the rotor to the gearbox.
- Main Frame: Made from steel. Must be strong enough to support the entire turbine drive train, but not too heavy.
- Cables: Link individual turbines in wind farm to an electricity sub-station.
- Gearbox: Gears increase the low rotational speed of the rotor shaft in several stages to high speed needed to drive the generator.
- Generator: Converting mechanical energy into electrical energy.
- Yaw System: Mechanism that rotates the nacelle to face the changing wind direction.
- Pitch System: Adjusts the angle of the blades to make best use of the prevailing wind.
- Power Converter: Converts direct current (DC) from the generator onto alternating current (AC0 to be exported to the grid network.
- Transformer: Converts the electricity from the turbine to higher voltage required by the grid
- Brake System: Disc brakes bring the turbine to a halt when required.
- Nacelle Housing: Light weight glass tire box coves the turbine’s drive train.
- Screws: Hold the main components in place , must be designed for extreme loads.
All these components is explained by detail in figure (23).
Figure (23) – Components of Wind Turbine
The integrated of the components in HAWT type is shown in figure (24).
Figure (24) – Assembly of HAWT
Old & Future Designs of Wind Turbines:
There are many engineering designs of wind turbines either for horizontal or vertical axis types has been made since decades.
Firstly, we will mention the old designs & they are:
1) Early Old Wind Turbine (VAWT-Drag Based):
The Persian windmill was used around 1000 b.c. to turn a grindstone. It is the oldest known windmill design. The machine works by blocking the wind blowing on ½ of its sails. The sails exposed to the wind are pushed downwind due to drag, causing the windmill to rotate.
Figure (25) – Persian Wind Mill
2) Anemometer (VAWT-Drag Based)
The anemometer is an instrument for measuring the speed of airflow. A cup anemometer is a drag-type vertical axis wind turbine
Figure (26) – Anemometer Device
3) Flapping Panel Wind Turbine
This illustration shows the wind coming from one direction, but the wind can actually come from any direction and the wind turbine will work the same way.
Figure (27) – Flapping Panel Wind Turbine
4) Savonius Wind Turbine
The Savonius turbine is S-shaped if viewed from above. This drag-type VAWT turns relatively slowly, but yields a high torque. It is useful for grinding grain, pumping water, and many other tasks, but its slow rotational speeds make it unsuitable for generating electricity on a large-scale.
Figure (28) – Different Types of Savonius Wind Turbine
5) Darrieus Wind Turbine
The Darrieus turbine is the most famous vertical axis wind turbine. It is characterized by its C-shaped rotor blades which give it its eggbeater appearance. It is normally built with two or three blades.
Figure (30) – Darrieus Units in WT Farm
A Darrieus is a type of vertical axis wind turbine (VAWT) generator. Unlike the Savonius wind turbine, the Darrieus is a lift-type VAWT. Rather than collecting the wind in cups dragging the turbine around, a Darrieus uses lift forces generated by the wind hitting aero-foils to create rotation.
We will discuss it technically of how it works as there are many people don’t understand it clearly.
The working principle of Darrieus rotor can be simplified as we see in figure (31).
Figure (31) – Working Principle of Darrieus Wind Turbine
First, assume that the retarded wind in front of the rotor still remains straight. When the blades are moving much faster compare to the original undisturbed wind speed i.e. ratio of blade speed to free stream wind speed, tsr > 3, the figure (30) above shows the velocity vector of the airfoil blades at different angular position.
With such a high tsr, the airfoils will be ‘cutting through’ the wind with small angle of attack. The resulting lift force always assists the rotor rotation while the drag force always opposes the rotation. As the lift zeroing at the left side (0 degree) and right side (180 degree) where the symmetrical airfoil moves paralleled to wind, the torque changes to negative around these position.
At the near front (90 degree) and far back (270 degree) position, the lift component is much higher than the drag component, so positive torque is produced. The total torque per revolution will be positive with a good set of airfoils so the rotor will accelerate at the right direction.
During startup, the starting torque depends on the angular position of rotor with respect to the wind direction, so the rotor might rotate at the right direction straight away or wobble a bit before starting. Normally, the rotor will need some form of assistance to reach higher rpm before it begins to rotate by itself as the Darrieus rotor has very low torque at low tsr which can be easily worsened (till negative) by friction in the system.[Ref-7]
Figure (32) – Integration between Savonius & Darrieus
6) Giromill Wind Turbine
The Giromill is typically powered by two or three vertical aero-foils attached to the central mast by horizontal supports. Giromill turbines work well in turbulent wind conditions and are an affordable option where a standard horizontal axis windmill type turbine is unsuitable.
Figure (33) – Giromill Wind Turbine
8 ) Cyclo-Turbines:
Another variation of the Giromill is the Cycloturbine, in which the blades are mounted so they can rotate around their vertical axis. This allows the blades to be “pitched” so that they always have some angle of attack relative to the wind.
The main advantage to this design is that the torque generated remains almost constant over a fairly wide angle, so a Cycloturbine with three or four blades has a fairly constant torque. Over this range of angles, the torque itself is near the maximum possible, meaning that the system also generates more power. The Cyclo-turbine also has the advantage of being able to self start, by pitching the “downwind moving” blade flat to the wind to generate drag and start the turbine spinning at a low speed. On the downside, the blade pitching mechanism is complex and generally heavy, and some sort of wind-direction sensor needs to be added in order to pitch the blades properly. .[Ref-7]
Figure (34) – Cycloturbine
9) Horizontal Axis Wind Turbines (HAWT):
A horizontal Axis Wind Turbine is the most common wind turbine design in the world. In addition to being parallel to the ground, the axis of blade rotation is parallel to the wind flow.
Figure (35) – HAWT in Land
Figure (36) – HAWT on Seawater
10) Shrouded Wind Turbines (Ducted Wind Turbine – DAWT)
Some turbines have an added structural design feature called an augmentor. The augmentor is intended to increase the amount of wind passing through the blades (Increasing the velocity, will increase the power of wind turbine).
Figure (37) – Shrouded WT
There are also new design which opposite to the shrouded wind turbines as we see in figure (38). The purpose of this design is create a vortices in the outer frame of cone tire.
Figure (38) – New Design of Ducted Wind Turbine
This action will let to establish a low pressure zone in the exit of the cone, which lead to increase the power of the wind turbine.
There is also another design which similar to above definition as we see in figure (39).
Figure (39) – Flo-Design Wind Turbine
It’s named as “Flo-Design’s Jet Engine Turbine” (Its company has been renamed from “Flo-Design” to “Ogin”).
Conventional wind turbines have greatly increased in size and height in recent years, but their fundamental design hasn’t changed much in decades. In fact, today’s standard turbines are based on the same physical principles as 18th century windmills.
The Ogin turbine is different.
Figure (40)- Flo-Design in Mountain
It’s unique shroud design takes advantages of the latest advances in the aerospace industry to change physical airflow patterns through & around the turbine.
Figure (41) – Aerodynamic Mechanism of Flo-Design Type
Annual energy output per KW of rated capacity is increased by 50%, while peak energy output from the ultra compact rotor is increased by up to 3 times per unit of swept area. The result as a quiet, compact 100 KW turbine that outperforms any other mid-scale turbine on the market. [Web-3]
Figure (42) – Parts of New Design
11) Vortex Wind Turbine
Figure (43) – Vortex “Bladeless” Wind Turbine
Vortex bladeless S.L is a Spanish tech start up that developed a multi –patented wind turbine without blades. In 2014, Vortex bladeless won “The South Summit Award “ in the category of energy & industry for the best project.
The idea emerged in 2002 when David Yanez , the inventor, saw a video of the Tacoma Narrows Bridge disaster in Washington state, USA and led him to the idea of a bladeless wind turbine.
Figure (44) – Tacoma Bridge Accident in USA & effect of strong wind
Figure (45) – The Fall of Tacoma Bridge
The new technology seeks to overcome issues related to traditional wind turbine such as maintenance, amortizations, noise, environmental impacts, logistics & visual aspects.
Vortex’s innovation comes from its unusual shape, where fiber-glass & carbon-fiber mast oscillates in the wind taking advantage of the vortex shedding effect. At the bottom of the mast a carbon-fiber rod moves inside a linear alternator that generates the electricity, with no moving parts in contact. Vortex has a small carbon footprint, is noiseless, has low center of gravity and allows for small foundation dimensions, so more generators can be placed in an area, at twice the density of traditional turbines. [Web-4]
Figure (46) – The Future Game Changer for Wind Energy Technology
12) Quiet-Revolution Wind Turbine:
Figure (47) – Quiet-revolution Wind Turbine
The quit-revolution is a discontinued brand of (VAWT) vertical axis helical turbine. The helical design is most similar to the Gorlov Helical Turbine.
Both are an evolution of the Darrieus wind turbine. They has owned several awards including the “Sustainable Innovation Award” in 2006.
Figure (48) – Quiet-revolution wind turbine at the London Olympic Stadium
The turbine consists of three vertical airfoil blades, each having a helical twist of 120 degrees. This feature spreads the torque evenly over the entire revolution, thus preventing the destructive pulsations of the straight-bladed giromill (Darrieus turbine). The wind pushes each blade around on both the windward and leeward sides of the turbine.
The QR5 turbine, rated 6 KW, measures 3.0m in diameter by 5m height. Poor performance of the QR5 installed at Welsh government offices in Aberystwyth has been blamed on poor sitting. The turbine’s overall cost was given as 48,000 £ and in 2012 it generated an average of 33 KWh per month, a value of 5.28 £ per month.
Figure (49) shows a small Quiet-revolution QR5 Gorlov type vertical axis wind turbine on the roof of Colston Hall in Bristol, England. Measuring 3 m in diameter and 5 m high, it has a nameplate rating of 6.5 kW.[Web-5]
Figure (49) – Quiet-Revolution Turbine in Bristol, England
There has been designed the QR6 as the next generation of helical VAWT offering improved power generation, increased swept area whilst retaining the intrinsic.
The blades, spokes & torque tube are made of advanced composite materials including carbon-fiber for weight, reduction, stiffness and longevity. The brakes modified with enhanced anti-corrosive properties, increased power despite decreased energy consumption. [Web-6]
Figure (50) – Quiet Revolution Turbines
Note: Almost types of wind turbines may be found in Reference 5 (Ref-5).
Now, Let Us Talk About The Future Technologies of The Wind Turbines:
1) Airborne Turbines:
Figure (51) – Airborne Wind Turbine
Airborne turbine concepts have appeared, at least in patent documents, for many years, and such concepts are presently generating increased interest. The designs are broadly classified as [Ref-6]:
- Systems supported by balloon buoyancy;
- Kites (lifting aero-foils); and
- Tethered auto gyros.
Figure (52) – Airborne Wind Turbine (AWT) Type 1
Figure (53) – Another Airborne Wind Turbine (AWT) Type 2
Figure (54) – Working Mechanism AWT Type 2
Figure (55) – Design of Kite Airborne Type
Figure (56) – Mikani Kite exit from the Factory
Figure (57) – Mikani Kite Type in Site of Test
2) Electrostatic Generator:
An electrostatic generator is being investigated in the High Voltage Laboratory at TU Delft. It is presently at the laboratory feasibility stage, being tested at milli-watt scale. The considerable attraction is to have a system with few mechanical parts. It is seen as being potentially suitable for buildings, due to minimal noise and vibration, or for offshore, on account of simplicity and the potential to be highly reliable. [Ref-6]
Figure (58) – Dutch Wind wheel Diagram
3) Magnetic Levitation (Mag-Lev):
Figure (59) – Maglev Wind Turbine
Mag-Lev is an innovative vertical axis turbine concept. Construction began on a large production site for Maglev wind turbines in central China in November 2007. According to a press release, Zhongke Hengyuan Energy Technology has invested 400 million Yuan in building this facility, which will produce Maglev wind turbines with capacities ranging from 400 to 5000 kW. [Ref-6]
Figure (60) – 10KW Maglev Wind Turbine
Figure (61) –Maglev Wind Turbine in Life
Traditional wind turbines suffer from few drawbacks such as ; noise, friction, maintenance, birds (sliced by blades), turbulence & the speed of wind (the wind speed needed to drive a wind turbine is higher the bigger the turbine. For example, a smaller 1 KW house type needs about 8 mph (3.6 m/s) to start & continue rotating, while those large 100’ ones need about 20 mph+ to even start. A magnetic levitation wind turbine suffers none of the traditional turbines drawbacks. [Web-7]
Figure (62) – Comparison between Traditional (HAWT) & Maglev Wind Turbine
You may read this issue if you want to know more about it [HERE]
Global Markets & Economics of Wind Energy Technology:
The international markets of installations of wind energy technologies has been rapidly increased annually as we see in figure (63) & (64) which represent the annual & cumulative capacity of wind energy installation between 1997 & 2014.
Figure (63) – Annual Capacity
Figure (64) – Cumulative Capacity
China is the largest country which deployed & applied wind energy technologies in the world. Figure (65) & (66) shows the top 10 countries which are produce energy by exploiting the wind energy. [Ref-8]
Figure (65) – Cumulative Capacity Charts of Wind energy in 2014
Figure (66) – Cumulative Capacity Table of Wind energy in 2014
Among the main trends dominating the market of wind energy during the years, one may note the size increase of contemporary WTs (Wind Technologies), the efficiency improvement and the long-term reduction of the specific investment cost per kW (turnkey cost) of installed wind power capacity.
Concerning the latter, although starting from a remarkable 3500 €/kW during the mid-eighties, it has during the last years stabilized in the order of 1200 €/kW, i.e. between 1000 €/kW and 1400 €/kW, depending also on the area of study.
In this context, some rough numbers may also be given in terms of investment cost breakdown, noting also the difference between onshore and offshore applications.
More specifically, the turbine component being critical in onshore projects (~930 €/kW) as we see in figure (67-upper) drops to a typical 48% in offshore plants as we see in figure (68-upper), while on the other hand, foundation requirements increase by more than four times and grid connection in offshore is increased by more than 150 €/kW. Overall, the total specific investment cost of offshore applications is found to be higher by more than 40% for most of the plants in operation and may increase to even exceed 3000 €/kW for installations that are under construction. Besides, based on the experience of in operation offshore parks employment of more turbines implies relatively lower turnkey costs as it showed in figure (68-lower). [Ref-9]
Figure (67) – Breakdown of the Investment and the O&M Cost Onshore Wind Parks
Figure (68) – Typical Investment Cost Breakdown and Variation of Offshore Wind Parks’ Turnkey Cost
Any case given, M&O costs (see Figure 67 – lower) including insurance, regular maintenance, repairs, spare parts, administration, land rent and others , are also considerable for wind power installations, although the introduction of more efficient machines and the reduction of downtime hours constantly decrease the M&O requirements which are now in the order of 1.2~1.5 c€/kWh.
On the other hand however, the wind energy production cost is found to be comparable with the respective of conventional fossil fueled generation methods, even without internalizing the externalities. As a result, clear advantage of wind power in the economic field as well becomes evident (Figure 69 ), with estimations concerning the near future electricity generation cost of onshore and offshore wind parks supporting values between 50 €/MWh and 80 €/MWh and between 75 €/MWh and 120 €/MWh respectively.[Ref-9]
Figure (69) – Estimation of Energy Generation Production Cost for 2020
Environmental Impacts of Wind Technology
Although suggesting an a-priori clean energy source, wind power also comes with certain environmental impacts such as the visual and the noise impact, the land use, the bird fatalities, the electromagnetic interference, the impacts on fish and marine mammals and the embodied energy plus LC emissions common in every power generation technology.
Many of these impacts are nowadays perceived by many as “myths” (see figure 70) while others still lie on the subjectivity of oneself. What is documented however is that WTs require primary LC embodied energy amounts in the order of only 1~3 MWh/kW (that usually implies energy payback periods of months), with the stage of manufacturing being the most demanding.[Ref-9]
Figure (70) – Causes of Birds Fatalities
Furthermore, if also considering externalities, a clear advantage may be recorded for wind power installations in comparison with conventional power plants as we see in figure (71). [Ref-9]
Figure (71) – Global Warming Potential
In fact, according to estimations, realization of the high expectations set by the EU for 2020 implies avoidance of externalities in the amount of almost 40 billion €/year, with the distribution of cost savings per country given in Figure (72). [Ref-9]
Figure (72) – The Avoidance of External Costs for EU-2020
Besides that, environmental performance of wind energy perceived by the majority of people (over 70% in favor) and transformed in to widespread social support (only solar energy seems to be more socially accepted) further boosts wind energy developments.
On the other hand, one of the challenges that wind energy is faced with during the recent years is the paradox of increased social support being obscured by real-life NIMBY attitudes, especially since availability of good sites is becoming increasingly rare. [Ref-9]
NIMBY: Not In My Back Yard
Figure (73) – NIMBY
Techniques for Increasing the Wind Power:
The power of wind turbine per area has been considered as a high priority for many companies & countries. It will reduce the capital cost of wind farm.
Now, why we can’t obtain high power from wind turbine ?
As we remember, there are maximum efficiency (power coefficient) of wind turbine which can’t be exceeded, named as “Betz’s limit” (Cp = 59.3%) according to the design of HAWT turbine, so we can’t do anything about it.
Figure (74) – Betz’s Limit with Speed Ratio Graph
Figure (75) – Comparison between Wind Turbines efficiency & Betz’s Limit
In mathematical language, the total & output maximum theoretical power of wind turbine may be represented by the equation :
Losses may be (disturbance, design of blade, vortices, stall, friction)
Or the alternative equation of turbine power may be written as:
Now there are 3 ways to increase the power of wind turbine (as the power coefficient/efficiency will be excluded as it related to Betz’s limit). The parameters are:
- Density of air.
- Area of turbine.
- Velocity of air.
Variation of air Density will not make a significant change in the power of turbine . Area of turbine blades has a direct proportional to the initial cost of manufacturing.
The last parameters is velocity, which is turbine power has direct proportional relationship to the cube ( the third power ) of average velocity of air.
If the average velocity of air is 1 m/s, then the power of wind turbine will be 0.85 Watt (Assume the radius of turbine blades is 1m, density of air is 1.2 Kg/m3 & the CP is 0.45 ).
Now, if the velocity is 2 m/s, the power will be multiplied by 8 (V3=2*2*2=8). The power will be 6.79 Watt for the same area & density.
So, it seems that increasing the average velocity of wind is the more preferable & best choice for increasing the wind turbine power, but how we can do such matter ?
Suppose that we have a convergent cone as we see in figure (76).
According to the continuity equation, the mass flow rate is constant in any section of convergent cone & it is represented by equation :
The density & mass rate will remain constant, so the area of cone has a inverse proportional relationship with velocity as:
Now, how we can obtain velocity of 40 m/s from initial velocity of 2 m/s & outer area of 1 m ?
The inner area of convergent cone must be equal to:
The power of wind turbine without convergent cone is 6.79 Watt similar to the previous example .
After using the convergent cone, the new power of wind turbine will be 54.3 KW.
Wonderful, isn’t ? It’s very high power for small area of wind turbine.
If it’s very simple idea, why it doesn’t spread widely in the world ?
Actually, it has been done but for very small size of cone as we see in the designs of shrouded turbine.
Figure (77) – Shrouded Turbine [Wind-Tamer]
But we want to obtain 40 m/s, so we must elongated the cone for long distance more than 7m as equation of cone (by assuming that angle of cone “θ” is 15 Deg):
Ok, why we don’t elongate it in real life for Wind Turbine?
The problem is related with shear force (viscosity force) & surface friction of convergent cone material of air motion & the angle of cone.
Shear Force (Viscosity Friction):
If you have ever drifted in a boat on a gentle river, you may have noticed that your boat moved faster in the middle of the river than very close to the banks. Why would this happen?
Figure (78) – Effect of Viscosity of River in Boat
If the water in the river were an ideal fluid in laminar motion, it should make no difference how far away from shore you are. However, water is not quite an ideal fluid. Instead, it has some degree of “stickiness” called viscosity.
For water, the viscosity is quite low; for heavy motor oil, it is significantly higher, and it is even higher yet for substances like honey, which flow very slowly. Viscosity causes the fluid streamlines at the surface of a river to partially stick to the boundary and neighboring streamlines to partially stick to one another.
The velocity profile for the streamlines in viscous flow in a tube is sketched in Figure (79). The profile is parabolic, with the velocity approaching zero at the walls and reaching its maximum value in the center. This flow is still laminar, with the streamlines all flowing parallel to one another. [Ref-10]
Figure (79) – Ideal & Viscous Fluid Flow
The law which is measured the viscosity effect is :
τ_w : Shear Stress. (Pa)
h: height from the ground to the object surface.(m)
Δv: relative velocity between the object & ground.(m/s)
The shear force which always parallel to the exposed area of surface by force. It’s called Newton’s Law of viscosity.
The unit of viscosity represents pressure (force per unit area) multiplied by time, or pascal seconds (Pa s). This unit is also called a poiseuille (Pl). (Care must be taken to avoid confusing this SI unit with the cgi unit poise (P), because 1 P = 0.1 Pa s.)
It is important to realize that the viscosity of any fluid depends strongly on temperature. You can see an example of this temperature dependence in the kitchen. If you store olive oil in the refrigerator and then pour it from the bottle, you can see how slowly it flows.
Heat the same olive oil in a pan, and it flows almost as readily as water.temperature dependence is of great concern for motor oils, and the goal is to have a small temperature dependence. Figure (80) lists some
typical viscosity values for different fluids. [Ref-10]
Figure (80) – Typical Viscosity of Some Fluids
For circular pipes, the shear force may be calculated by:
F_w : Shear Force on Wall of pipe (N)
τw : Shear Stress (N/m2).
A_w : Circumference Area of pipe (m2).
D: Diameter of pipe.
L: length of pipe.
As the flow is in equilibrium,
Driving Force = Retarding Force
ΔP is pressure difference between the entrance & exit of the pipe.
The last equation is represented pressure loss in a pipe in terms of the pipe diameter and the shear stress at the wall on the pipe.
- In the laminar flow,
In general the shear stress τw. is almost impossible to measure. But for laminar flow it is possible to calculate a theoretical value for a given velocity, fluid and pipe dimension.
The pressure loss in a pipe with laminar flow is given by the Hagen-Poiseuille equation:
Where, v is the mean velocity (not the maximum) or in terms of head:
Where hf is known as the head-loss due to friction & “g” is the gravitational acceleration (g=9.81 m/s2).
In the Turbulence flow,
The equation which is governed the turbulence flow is equivalent to the Hagen-Poiseuille equation for laminar flow with the exception of the empirical friction factor f introduced:
Equation  is known as the “Darcy-Weisbach Equation” for head loss in circular pipes (Often referred to as the Darcy equation).
“f” is the friction factor & it values depend on the surface roughness of pipe material.
“C_f” is the skin friction coefficient or Fanning’s friction factor. [Ref-11]
In addition to head loss due to friction there are always head losses in pipe lines due to bends, junctions, valves etc. For completeness of analysis these should be taken into account. In practice, in long pipe lines of several kilo-meter their effect may be negligible for short pipeline the losses may be greater than those for friction.
General theory for local losses is not possible, however rough turbulent flow is usually assumed which gives the simple formula :
Where hL is the local head loss and kL is a constant for a particular fitting (valve or junction etc.)
For the cases of sudden contraction (e.g. flowing out of a tank into a pipe) of a sudden enlargement (e.g. flowing from a pipe into a tank) then a theoretical value of kL can be derived.
For junctions bend etc… kL must be obtained experimentally.[Ref-12]
Figure (81) shows the engineering simulation for air stream in sudden expansion duct by using ANSYSY FLUENT software. The air moves from the right by velocity of 20m/s & we notice the creation of vortex (eddy current) in figure (81-B) which it is considered as a loss energy. Figure (81-C) represent the velocity contours of air.
Figure (81-A) – Velocity Vectors Profile of Air in Sudden Expansion by using ANSYS Fluent
Figure (81-B) – Velocity Vectors Profile of Vortex in Sudden Expansion Duct
Figure (81-C) – Velocity Contours Profile of Air in Sudden Expansion Duct
There are many energy losses similar to the sudden expansion & contraction duct, such as;
- Pipe entrance or exit.
- Bends, elbows, tees, and other fittings.
- Valves, open or partially closed.
- Gradual expansions or contraction.
Now, let’s explain how it will affect the friction loss of pipe or cone in the final velocity go fluid (water/air).
Figure (82) shows the flow of fluid in pipe which has a different diameter (d) & height (z).
Figure (82) – Bernoulli’s Equation for Fluid Pipe
The Bernoulli’s equations associated with friction head is represented in equation [20 ]:
Now, let us to solve a simple example to understand how the length of pipe may effect on the pressure difference in the pipe/cone.
Assume that we have horizontal pipe (z1=z2) with the same diameter of p0ipe in the exit & entrance (d1=d2) , then the velocity will remain constant in steady flow.
The data of this example as follows for air;
Entrance Pressure (P1) = 101 KPa
Entrance Pressure (P1) = 100 KPa
Velocity = 2 m/s
Density of air = 1.2 Kg/m3
Diameter of pipe = 0.5 m
Dynamic Viscosity of air (μ) = 1.8X10-5 Pa.s
Find the maximum length which let the air moved towards the low pressure zone.
To find the maximum length of pipe, we should calculate the head loss by :
We must find the friction factor by using Moody chart to calculate the loss head, then the length of pipe. But, firstly we should find Reynolds number (Re) to determine the flow either it’s laminar or turbulence for deciding the suitable equation to be used for evaluating the friction loss head.
The Reynolds number of our data may be found by :
The air flow is turbulence, then we will use Moody Chat to find the friction factor (depend on the pipe metal & we will assume that we use riveted steel with roughness of 0.4 mm, then the relative roughness
So according to the Moody chart for Reynolds Number of 66,666 & relative roughness of 0.0008, we may get the friction factor “f” equal to 0.021 approximately as we see in figure (83) which represent a Moody chart.
Figure (83) – Moody of Chart for the Example
Then, we will substitute that value of friction factor in equation  to find the maximum length of pipe for air flow:
Difference of pressure 1 KPa (1000 Pa) for area of 1 m2, will create an exerted force equal to 1000 N.
This force may move mass of body equal to 100 Kg (by assuming gravity acceleration 10 m/s2). That means it can move human body with mass of 100 Kg (220 lb) from place to another.
Definitely the ordinary & daily wind can’t do that action unless it being tornado/hurricane.
Figure (84) – Joplin Tornado Effect in Missouri, USA on May 2011
So, the pressure difference of wind must be less than what we assume previously (P<1000 Pa).
Now, if the entrance pressure is 100.1 KPa, the maximum length of pipe will be 1 m approximately.
The maximum length will be 0.1 if the pressure difference of wind is 10 Pa.
And don’t forget we are talking previously about pipe. Cone will have more losses.
For that reason, the wind turbine don’t have a long pipe/cone to override that complexity & undesirable situation for friction loss which affected negatively in the power of the wind turbine.
But wait, we have a creative solutions to utilize from a long convergence cone to increase the power of wind turbine.
As we see previously in equation  that viscosity/friction loss has a relationship with velocity which effect directly in the difference of pressure between the entrance & exit of pipe:
Equation  represent the relationship between the pressure difference & velocity of fluid:
The velocity in the numerator of the equation  may be considered as the relative velocity of fluid (liquid/gas) in respect to the wall of pipe:
When the velocity of wall is zero, the relative velocity will equal the velocity of fluid.
Now, suppose that we have a special method to move the wall by specific velocity less than the velocity of fluid.
Figure (85) –Stationary & Movable Wall
The relative velocity will consequently decrease. That’s means the pressure difference has been reduced.
This simple concept of wall motion will be the basic idea to increase the power of wind turbine by using convergence cone.
Now let us give some creative ideas for the concept of wall motion & mention techniques for increasing the power of wind turbine .
1) The Pulley-Convergence Cone System :
Figure (86) – Pulley Convergence Cone Wind Turbine
As we see in figure (86), the new wind turbine design is associated with pulleys & belt system.
As we know the velocity of wind will varied from the entrance to the exit (before the wind turbine zone) of the convergence cone as a result of change in the radius of the cone along the length of it.
If we plot the velocity against length of cone in graph for the previous example, we will notice that we may obtain a linear relationship as we see in figure (87).
Figure (87) – Curve Graph of Velocity with Cone Length
The linear equation of this graph is :
Where “m” is the slope of line in “length–velocity” graph & it can be found by:
By using integration method for equation  to find the area (rectangular & triangle area), we will find that :
Then, divided it by the length of the cone, we will find the average velocity of wind as it’s explained in equation :
Then, the average velocity will be:
This average velocity will be the speed of the belt in pulleys system.
Then, we will calculate the difference tension of force in belt according to the “Machines Theory” to find the power of driven pulley motor as equation  :
Where “T1 & T2” is tension force in the tight & slack part respectively.
Figure (88) – Pulley Motion in Belt System
The friction force may be appear in the outside the system as the surrounded outside wind direction will be opposite to the direction of belt motion. But that problem can be solved by put the pulleys system in box.
Someone will tell that the cone is cylindrical shape in real life not rectangular.
Yes I know, thinking by yourself how you can solve this difficult issue or design a rectangular cone which can achieve the maximum power.
2) The Outer Wind/Vortex Ejector System:
When the blade of the turbine operated, a part of the kinetics energy will be reduced from the total energy.
Then, it will create a pressure difference (low & high pressure zones) between the exit & outer circumference of the wind turbine as we see in figure (89) & if the pressure difference is very large (in the high speed wind), a vortex will established, and it will impede the blade motion to decrease the output power.
Figure (89) – Effect of Vortex on Turbine Power
There are possible two solution for this issue,
One of this solution, is to utilize from the outer wind to operate an internal blade along the exit cylinder/rectangular of the wind turbine as it shown in the figure (90).
Figure (90) – First Solution of Vortex Drawbacks
There are a conic/triangle shape inside the exit cylinder/rectangular to increase the velocity of inner air (due to the reduction of the area).
The outer wind will reduce its kinetic energy as a result of losing a part of the kinetic energy to the small auxiliary wind fans in the exit cylinder./rectangular. The inner air will gain this energy.
By suitable design of the exit cylinder & cone, the final pressure difference may be modified to be approximately zero. The velocity of both inner & outer air will be same.
Don’t forget that there are another layer will also be created in the same manner of establishing vortex as a result of pressure difference at the upper circumference part of the outer airstream as we see in figure (), but it will not affect the power of wind turbine at all .
There is another method without change the speed of outer air stream:
Figure (91) – Second Solution of Vortex Drawbacks
The second method, is depend on using the vortex – which is created on wall – to rotate the small auxiliary wind fan. Figure (91) shows the components of the second solution.
We must talking briefly about the “Vortex” & how it created for more understanding the other methods.
In fluid dynamics, a vortex is a region in a fluid in which the flow rotates around an axis line, which may be straight or curved. The plural of the vortex is either vortices or vortexes.
Vortices form in stirred fluids, and may be observed in phenomenon such as smoke rings, whirlpools in the wake of boat, or the winds surrounding a tornado or dust devil.
Vortices are a major component of turbulent flow. The distribution of velocity, vorticity (the curl of the flow velocity), as well as the concept of circulation are used to characterize vortices. In most vortices, the fluid flow velocity is greatest next to its axis and decreases in inverse proportion to the distance from the axis.
In the absence of the external forces, viscous friction within the fluid to organize the flow into a collection of ir-rotational vortices, possibly superimposed to larger-scale flows, including large-scale vortices. Once formed, vortices can move, stretch, twist, and interact in complex ways. A moving vortex carries with it some angular and linear momentum, energy and mass.
In theory, the speed “U” of the particles (and therefore vorticity) in a vortex may vary with the distance “r” from the axis in many ways. There are two important special cases however;
1) If the fluid rotates like a rigid body – that is , if the angular rotational velocity “ω” is uniform, so that “U” increases proportionally to the distance “r” from the axis.
2) If the particle speed “U” is inversely proportional to the distance “r” from the axis, then the imaginary test ball would not rotate over itself, it would maintain the same orientation while moving in a circle around the vortex axis. [Web-8]
Figure (92) –Vortex created by the passage of an aircraft wing
- How we can use the concept of vortex for increasing the power of the wind turbine ?
Similar to the previous method, it will be installed small rotational air turbine in the outer circumference of the cylinder/rectangular as we see in figure (91). Then, it will connected with the air fan which may increase the velocity of inner air.
We may add the ejector system to the pulleys convergence cone as we see in figure (93) to increase the power of wind turbine incredibly.
Figure (93) – Combination of Pulley & Ejector System
3) The Cone Box:
As we know, the vortex effect is appear on the upper part of wind turbine circumference as we see in figure (94). If the speed of wind was very high, it will increase the vortex & occupied more area in the turbine circumference which lead to more loss of power.
Figure (94) – Effect of Vortex in Wind Turbine Blades
There are two solution.
First method is to make a convergence cone next to the exit of wind turbine. This cone will be surrounded by rectangular /cylindrical shape which will connected with pulleys & motor system similar to the first idea of increasing the power of wind turbine.
When the vortex is created, it will affect only on the circumference part of the fixed rectangular/cylindrical shape as we see in figure (95). The exit air stream from the turbine will eject from the center of the shape.
Figure (95)- Cone Box Pulley Type
The second method is concerned with the variation of velocity along the rotation axis of the vortex. As we know there a type of vortex which has a uniform angular velocity “ω”, so the velocity along the axis of rotation may be calculated:
Now, if we let the air which is rejected from the wind turbine, be discharge from the center of the vortex as we see in figure (96), then we can overcome the negative effects of the vortices toward the wind turbine.
Figure (96)- Cone Box Vortex Type
4) The Exit Vortex Fan:
The vortex fan is shown in figure (97) will be mounted in the intersection point of the outer divergence & inner convergence cone. The outer divergence cone has been used to increase the size of the vortex.
The vortex fans will increase the kinetic energy of discharged air from wind turbine.
Figure (97)- Exit Vortex Fan
5) The Curved Paths of Vortex:
There is another way to utilize from vortex without using any fan by establishing a curved paths near the exit of air stream as it shown in the figure (98).
Figure (98)- The Curved Paths of Vortex
What happen exactly in that situation, is similar to move a plate on the seawater. The motion force of plate will compel the water to move with the plate in the same direction as viscosity effect. The force will act as Reverse Shear Force as it effects on the circumference, not in the center of fluid . It depends on the viscosity factor to move the stationary fluid. Here in our example, we have a full circumference air force in the exit of convergence pipe, which will governed the motion of air stream along the exit pipe.
6) Water Fall Concept:
There are two methods to utilize from the water fall to increase the power of wind turbine, and they are;
1) Air Bucket Ejector
Figure (99)- Air Bucket Ejector
As we see in figure (99) there are a wheel in the end of wind turbine with long arms connected with special buckets.
The water fall must be relatively have curved path & high velocity to assure the parabolic shape creation of water fall as we see in figure (99).
The steps of this idea is explained as follows:
1) The bucket will initially take a volume of air when the other side of connected arms is touched by the water fall. The second bucket has bee hidden for a reason which will be understand It later.
Figure (100) – Charging the Air Bucket
The air bucket will rotate until reach to outside layer of water fall & then air will be released due to hide the bucket as we see in figure (101) .
Figure (101) – Releasing Air from Bucket
When the other connected arms enter the region between the water fall & wind turbine, a special mechanism will activated to move the hidden bucket cylinder inside the arm upward to take new charge of air as we see in figure (102). In the same time, vice versa action will happen to other air bucket for discharging/releasing.
Figure (102) – The Components of Air-Water Wheel
The purpose of special mechanism, is to prevent fill the bucket with some of water when it enter that region, as it will decrease the efficiency of the air bucket ejector, then the power of wind turbine.
2) Water Inclined Holes Plates
The main feature of this idea is to utilize from the water motion as a driving force of exit air from wind turbine.
As we see in figure (103), there are multi-layers of inclined plates which have some hole on it. When the water is fall from the upper to next layer, the air will move more easier (less friction) as the motion of water on plate surface will act as lubricants in engines. The angle of inclination play important role for determining the speed of flow water which is related to the height & type of wind turbine.
Figure (103) – Water Inclined Holes Plates with Wind Turbine
The upper part of plate must be very smooth (frictionless) as possible & we will use small pump to feed up the water tank.
7) Natural/Artificial Borders Concept:
The eddy current or vortices will be established behind the wind turbine if there is an adjacent wind passed over the turbine.
Now, if we have stopped that adjacent wind by created a natural (e.g. trees) or artificial (e.g. homes & building ) borders. Then the pressure will reduce due to the reduction of velocity as we see in figure (104).
Figure (104) – Effect of Natural/Artificial Borders with Vortex
If there is a vortices creation it will be in the end of boarders apart from the wind turbine. This idea is preferable applied in desert or rural zones.
The disadvantages of this idea that we will need too much area to building/trees these boarders for the same traditional power of wind turbine without borders.
8) Rotational Ejector of 90 ⁰ System:
Figure (105) shows the components of the rotational ejector which are mainly comprised of movable piston, cylinder & fluid (lubricants) pipe connected with cylinders & finally a motor.
Figure (105) – Rotational Ejector System
The ejector system will positioned in the exit pipe of wind turbine as we see in figure (B-88).
Now let us analyze the working principles mathematically for this new concept.
Firstly, we must calculate the imaginary & ideal exit velocity from wind turbine. I mentioned it as imaginary because few loss has related to the friction & small vortices on the blades of turbine.
Let us assume the initial speed of wind is 7 m/s & capacity power factor (efficiency) of turbine is 45%. The atmospheric static pressure is 100 KPa. The density of air will be 1.2 Kg/m3.
Equation  represent the relationship between the gained & loss power:
So, the loss power will be:
And we remember previously that :
So, the loss power will be as equation  by substituting equation  in equation :
Then, we have equation  which is described the relationship between the initial & final velocity of wind by assuming that loss power are only a kinetic energy :
By using the previous data (speed = 7m/s & CP=45%), we will find that the final velocity is 5.74 m/s.
We will need to use the pulley & motor system to maintain this final speed of wind until reach to the ejector system. Any friction loss will be neglected. Figure (106) shows the first step of analyzing.
Figure (106) – Initial & Final Velocity of Wind Turbine
The total head of air in right side of turbine is determined by Bernoulli’s equation for status (1) & it will be :
So, the total head is 8496.41 m.
Secondly, the blue piston will be moved to the right due to the positive work of wind force (kinetic energy) as it’s shown in figure (107).
Figure (107) – Motion of Blue Cylinder
When it reach to its end, the blue cylinder will started rotate to prevent the creation of vortices which may affect negatively in the power of wind turbine. Friction of wall cylinder will reduce the velocity gradually. We can assume the velocity in status (2) is zero.
So, the total head inside the cylinder will equal to the static pressure head:
Figure (108) – Effect of Inner Vortex with Air Velocity
Thirdly, the blue cylinder will open when the angle of rotation reach 90 degree in respect to the axis rotation of wind turbine as we see in figure (109).
Figure (109) – Air inside Cylinder & Outer Wind
Now, what will happen between the outer wind (atmosphere) & the air inside the cylinder ?
It’s obvious that the head static pressure of both (outer atmospheric/wind & air inside cylinder) are equal, but they are different in the kinetic head.
The velocity head of air inside cylinder is zero (as the velocity is assuming zero) & the velocity head for outer wind is:
When a wind move horizontally in such situation as we see in figure (109), a vortex will be created due to the viscosity effect force between the upper layer of air inside the cylinder & lower layer of horizontal wind.
It’s “Free Vortex Flow” (ir-rotational vortex). The total energy head will be constant at any point of vortex by equation:
For free vortex:
C: constant of free vortex.
r: Radial distance from rotation axis.
Assume that the circumference layer of air has a similar velocity of outer wind which is 7m/s.
The total head of air inside the cylinder will remain constant, but the pressure head will change according to the equation ;
The final pressure in the upper layer of vortex will be:
Notice that the static pressure at status (2) is 100 KPa & it’s greater the static pressure of vortex which lead to not add any work to discharge the air from cylinder (with neglecting the friction effect of cylinder wall) as we see in figure (110).
Figure (110) – The Rejection of Air from Blue Cylinder
This previous processes will be repeated periodically.
9) The Large Elbow-Pulley System
One of the challenges encounter the energy industry by using wind technology, is concerned with the high capital cost of wind turbine components, especially the tower as it made by.
The purpose of high height of tower is to capturing the high speed of wind in that high location, as it has a direct proportional relationship with height above the ground.
So, Why we don’t collect that high speed wind & transfer it to turbine which is locates on a low level height for reducing the construction cost of tower ?
Figure (111) shows how we can do that idea by utilizing from the pulleys & motor system to save the kinetics energy of high speed wind from the friction losses.
Figure (111) – The Large Elbow Pulley System
The large elbow-45 Deg will be used & it may be manufactured by low cost material such as polyethylene (PE) or high density polyethylene (HDPE).
It obvious that the axis of rotation of wind turbine will be vertical, so the traditional HAWT has been converted to VAWT.
What will happen to the exit air is similar to the previous idea of rotational ejector system as the pressure of exit air will reduce due to the high speed of outer wind.
9) Ocean Slider-Pulley System (Offshore idea)
Ocean slider has the similar function of pulley-motor system as it will assist reduce the friction force due to the viscosity by decreasing the relative velocity between the neighbor air to the plate surface & the water as we see in figure (112).
Figure (112) – The Ocean Slider-Pulley System
The water plate will be positioned in specific angle according to the average velocity of wind in that region. Pumps will be used to fill the plate periodically.
We may use the pulley-motor system for the upper part of cone/triangle.
10) Inverted Double Wind Turbines:
The idea is similar to the pulley-motor system for one turbine but we have add another inverted turbine to utilize from lowering the pressure by using convergence cone for the outer wind between the exit pipe of two wind turbine as we see in figure (113).
When the wind enter the turbine, the velocity will decrease. Let us use our previous data of the example of idea “ Rotational Ejector 45⁰”.
Figure (113) – The Inverted Double Wind Turbine System
The speed of wind is 7 m/s, then the exit speed has been calculated as 5.74 m/s ( we assume the efficiency of turbine is 45%).
The static pressure of exit will remain constant as 100 KPa.
Now, in the convergence cone of outer wind, we may assume the area ration of cone is 2, then the velocity in the center of cone will be according to the continuity equation:
Remember that we are using pulley-motor system in the convergence cone to reduce the viscosity friction.
Now by using Bernoulli’s equation (neglecting the elevation head “z”), the static pressure of status (2) will be calculated by:
The static pressure in the end of convergence cone is less than the air which is discharged from the exit of wind turbine.
In the right side to the wind turbines, there is a convergence cone which is connected with vortices fans. It will prevent any drawbacks form outside wind.
It’s a unique concept to use two turbine & benefit from the low static pressure of outer wind in the intersection axis of the exit wind turbines.
11) Centered Large Cone Concept for 3-Blades Turbine:
I always asking myself, why the wind turbine has a long blades starting from the center of axis as we see in figure (114-A) ?
As we recall from physics of rigid rotation by fixed angular velocity “ω”, that the velocity in specific radius is depend on the equation  :
We know that the speed of wind is constant along the radius of turbine.
Figure (114) – The Effect of Speed Variation of Wind on Blade
So, don’t we are feeling mathematically that we are loss some of kinetic energy of wind by using a long 3-blades, as the point in the middle of radius will move in half of the speed wind as we see in figure (114-B) if we assume the velocity of tip blade will be similar to the wind speed ?
Why we don’t make the 3-blades as it showed in figure (115-B) to harvest this energy of wind energy & boost the power?
Figure (115) – The New Design of HAWT
Maybe the problem with the low quantity of air passed through the turbine (low out power), isn’t ?
Ok, we may use the concept of pulley-motor system to create long cone as it shown in figure (116) which can deflects the air stream into the blades, then the same quantity of air will be received by the new design of blades.
Figure (116) – Centered Large Cone Concept
The pulley-motor concept will be used to reduce the friction losses due to the viscosity. It’s named ‘Large” because the cone is very long.
There are a company named as “General Electric” (GE) has made few years ago a new design of wind turbine similar to my concept. It’s called “eco-ROTR” & it has a small cone similar to the dome (nose) as we see in figure (117).
Figure (117) – The eco-ROTR Wind Turbine Design of GE Company
“ It’s in desert, and it looks a little bit like a UFO” says Mike Bowman, who leads sustainable energy advanced technology at GE Global Research.
The company is testing the new 60-foot diameter dome – also variously compared to massive clown nose or Captain America’s shield – as a way to help turbines produce more power. It works by helping redirect wind energy that would otherwise be lost.
“On a wind turbine, the center part doesn’t do anything .” says Bowman. “It really has no ability to convert the wind into useful energy.”
The new attachment turns, and redirects wind to the widest part of the blades, where they can make the most use of it.
Engineers first started working on the design two years ago (2013), when the head of the research team challenged the designers to come up with a way for wind turbines to harvest more wind. After hacking together a model from Styro-foam ball, a toothpick, and mini-wind turbine, the team calculated that it would be possible to capture 3% more energy with the attachment.
Though 3% may be not sound like much, it makes a difference on a 1.7 Mega-Watt tower.
‘When you start looking at how many turbines are on a wind farm – maybe 100 –and adding up percentage on each one, it builds to a big number.” Bowman says. [Web-9]
I don’t know that, there are another talent people in this world thinking like me, as I was found this creative idea of cone/dome few a weeks ago when I was prepared this article , but my idea let us to elongate the cone for far distance by utilizing from the pulley-motor system, so we will decrease the construction cost of wind blades incredibly .
Imagine if we build a new design of wind turbine similar to figure (118), what will happen to capital cost & output power of wind energy technology ?
Figure (118) – The Combination of Convergence & Large Cone Concept
12) Geared Vortices Concept:
There is a another way to reduce friction due to viscosity by utilizing from vortices which is created as it shown in figure (119).
When there are a two fluid (air ) move in the same direction, two vortex will be established in the upper & lower part of wall which is positioned in the middle of the two fluid path.
As we see in figure (119) shows the engineering simulation by using ANSYSY FLUENT software of air stream in duct which have some rectangular blocks.
The air moves from the left by velocity of 20m/s & the triangle will reflect the direction of air as we see in figure (119-A).
We noticed obviously that there are two vortex (eddy current) has been created in figure (119-B) which is similar to gears in automobile. Figure (81-C) represent the velocity contours of air/wind in the duct.
Figure (119-A) – Velocity Vectors Profile of Air/Wind in Rectangular Block Units by Using ANSYS Fluent
Figure (119-B) – Velocity Vectors Profile of Two Vortex in the Duct
Figure (119-C) – Velocity Contours Profile of Air in the Duct
We can make the same concept with wind turbine as we see in figure (120).
Determining the suitable height & length of borders (wall) of geared vortices are important parameters for succession of this idea
Figure (120) – The Geared Vortices Concept
13) Turbo-Charger Wind Turbine:
We have discussed previously the matter of how we can utilize from the creation of vortices for increasing the power of wind turbine.
Here we will talk by the same concept but by utilizing from the idea of turbo-charger device in wind turbine.
In automobile industry, the turbo-charge is a turbine-driven forced induction device that increases an internal combustion engines efficiency & power output by forcing extra air into the combustion chamber. This improvement over a naturally aspirated engine’s power output is due to the fact that the compressor can force more air – and proportionately more fuel – into the combustion chamber than atmospheric pressure (and for that matter, ram air intakes) alone. [Web-10]
Now, let us apply that creative idea in wind industry.
We can built a special & lightweight rotational cylinder which have an outer blades of turbine to capture the high speed of outer wind by utilizing from the pulley-motor system as it shown in figure (121). The inner blades of fan (which can consider it as the compressor in turbo-charger device) is located in the exit of the wind turbine to compensate some of the loss wind energy which is absorbed by turbine in form of electricity generation.
Figure (121) – Turbocharger Wind Turbine
Turbocharger wind turbine concept will prevent the creation of negative vortices in the back side of wind turbine as the velocity in the outer cone & circumference of rotational cylinders.
14) Advanced Flo-Design System:
When I see the Flo-Design turbine as we see in figure (122-A), I have analyzed the situation & understand the reason behind why the power of such turbine is increased as it related to utilize from the viscosity force & high speed of wind.
So, I was thinking to developed new design which has more power than the traditional Flo-Design Turbine & the result is shown in figure (122-B).
Figure (122) – Recent & Advanced Flo-Design System
That’s all what I can to disclose for this idea. Start analyze the principles of it by yourself & it’s better to use simulation software such as ANSYS Fluent to find answer for your questions .
New Designs of Wind Turbines:
I have some design ideas for wind energy industry which I like to share it with experts & professional who are interested to find creative technologies, and they are:
1) Dual Power (Lift & Drag Type) Concept:
Wind turbines regardless it’s classification, it depend on either by lift (e.g. HAWT type) or drag (e.g Savonius WT Type) force, so why we don’t make a new design of wind turbine which is mixed two forces (lift & drag) together to increase the density of wind power per area of land ?
One of designs which I suggested is shown in figure (123-A).
The components of new design is very simple as it contains a HAWT system as the main part which is covered in the circumference by curved/inclined drag blades. Figure (123-B) shows these components.
Figure (123) – The Dual Power System
Although it will increased the cost of wind turbine, but we must determine the economical feasibility of such design as it may be more worth than using HAWT separately.
The pulley-motor system will be used for the inclination drag blades to reduce the negative effects of the viscosity of elbow surface.
I have also a proposed idea related to lift & drag force in general.
If we can manufacture blades as it shown in figure (124) which is contained the two forces, it may increase the output power of any turbine.
Figure (124) – Drag & Lift Combination in One Blade
2) Air Train Plates Concept:
Figure (125) – Old Ship Moved by Wind Force
Old Ships & sail boats have been moved in seawater by utilizing from the wind energy in the past ages & era. Still today has been used by some peoples for fun trips & sports competitions.
So, why we don’t design a plates which move like sailboats in the upper layer of high speed wind zones as it shown in figure (126) ?
Figure (126) – Air Train Plates Concept
There are two stations which are represent like transmission & receiving signal points in communication towers (satellites). This stations are connected with strengthened wire which is allowed to put on it a pulley as it shown in figure (126).
The frame of plate may be built from wood/plastic material to reduce the weight of plate & accelerated the plate to maximum velocity in short time by wind force.
The cover can be fabricated by sailcloth or Polyethylene bags which can be fold it later to be send it again easily to the transmission station.
There are 3 ways to resend the plate to the initial station & they are:
- Plates with Small Wheel (gravitational effect).
- Plates on Belt System.(electric effect).
- Plates sliding on water (gravitational effect).
Figure (127) shows all these methods & I don’t think it wants any explanation.
Figure (127) – Methods of Resending the Air Plates.
For any change in wind direction, there is an rotational system in the second station which let the station to rotate for specific angle. Definitely & it’s impossible in normal circumstance, that the direction of wind will exceed 90 degree. So, the rotational path of station 2 will be built according to that angle. Figure (A-7) shows the idea of rotation for station 2.
For the changing the direction of strengthened wires for simplifying the rotation of station 2, we can put a connected vane (similar to the vane tail in HAWT- upwind turbine) in the right & left sides of wire connections for a specific distance along the wire as it shown in figure (128).
Figure (128) – Changing The Direction of Station & Strengthened Wire
The capital cost of this kind of idea (as I guess) will be very low compared with construction of HAWT for the same output power.
The interruption of operation is the main disadvantages as we should wait a short period of time before we put the new plates on the wire.
This concept has been done in cables cars for skating & viewing the beautiful scenery from mountains.
Figure (129) – Car Cables
3) Linear Transitional Wind Energy Generator (LTWEG) Concept:
As we know, there are two types of magnetic field to produce electricity as it shown in figure (130). The types are :
- Rotational Type; Produce direct current (DC).
- Linear (displacement) Type: Produce alternate current (AC) if its fluctuated periodically.
Figure (130) – Produce Electricity by Magnetic Filed Phenomenon
All wind turbine types are based on the rotational type to produce electricity (DC), then we should use converter if we want to connect it with the public electricity grid in the country.
Let us introduce a new concept for producing electricity by the linear magnetic type.
Figure (131) shows the new ideas of linear transitional generator.
Figure (131) – Linear Transitional Wind Energy Generator
The components of the new system are:
1) Linear Magnetic Field Box
2) Two kinds of airfoil blades with different faces angles (figure A-73).
3) Direction changer device of wind (cone/triangle).
4) Small wheels for easy motion of system.
5) Electronic Sensor for changing the direction of cone/triangle device.
How it works ?
1) When the wind is come to hit the first type of blades –blue boxes- which is shown in figure (132), the lift force due to aerodynamic airfoil force will compel the system to move perpendicularly to the wind motion [upward motion in the right side of figure (132 )].
Figure (132) – Motion of Blue Blades in LTWEG
2) When the system reached its limit distance for first type blades (blue boxes), the sensor will give an electronic signal to the changer device for changing the direction of wind to be reflected to the second type blades –red boxes- as we see in figure (133).
Figure (133) – Motion of Red Blades in LTWEG
3) By changing of wind direction periodically, the result will be linear motion which is fluctuated to produce AC current.
To utilize efficiently from the wind energy & increase the speed of the movable part in system, we may design the array of blades as it shown in figure (134) for increasing the acting force on the blades.
Figure (134) – Multi Arrays of Lift Blades for LTWEG
The new idea may be used for high altitude to gain high speed wind by using the tower similar to the HAWT.
There is a way to convert the linear to rotational motion but it will be complicated matters which I don’t prefer it.
After I find this design & prepared this article, I have searched on the internet to find if anybody has design the same concept.
There are a company named as “ Linear Technologies Pty Ltd” located in Australia. They have been established the company to encompass the development work on wind energy extraction systems including the linear wind turbine generator (LWG). [Web-11]
Figures (135) & (136) show some photos of their creative design. The operating principles is shown in figure (137).
Figure (135) – LWG System
Figure (136) – LWG System
Figure (137) – Operating Principles of LWG
Rotational magnetic mean it’s DC current, so if we want AC current directly from the generator we can use my concept as it fluctuated linearly.
4) Combination of Tidal & Wind Offshore Turbines Concept:
Figure (138) – Offshore Wind Turbine
The main construction of this concept is similar to offshore wind turbine, but we will add a 2 large tidal wheel/turbine in the end of wind tower to increase the power by gaining from the tidal energy. Figure (139) shows the components of this idea.
Figure (139) – Combination of Tidal & Wind Offshore Wind Turbine
Water & wind motion are approximately moved in the same direction. So, the two wheel will utilize from wind & water simultaneously. The oceanic turbine system may be rotated according to the motion of seawater/air stream as it shown in the up right corner of figure (139) which represent the horizontal view of new system.
The water droplet device may be used to reduce the friction of curved plates by utilizing from the gravity. The curved path must be designed well to let water drops in the end part of curved plate. The shear force of land is greater than ocean because it is move relatively with wind motion. That’s the reason why we gain more power from offshore rather than onshore farms for the same capacity & engineering specifications of HAWT type for low height.
We can also use the pulley-motor system to do the same function.
The blades of tidal turbine may be designed according to the aerodynamic airfoil of lift force, but we must change the position of tidal turbine face to be in front of the tidal. In another words, the rotation axis of tidal turbine must be parallel to the ocean motion direction.
We can cover the blades of tidal turbine by High Density Poly-Ethylene (HDPE) to prevent any corrosion in the parts of it to reduce the maintenance cost.
5) Free Fall of Wind Turbines Concept:
Figure (140) – People fall from sky
It’s the last & unique concept which I like to share it with experts & professionals of wind industry for producing electricity by utilizing from the free fall phenomenon by gravity.
We will discuss it in detail mathematics & physical equations to reflect the significant & the importance of this concept to the wind technology industry.
When a body fall from high altitude, the speed of body will increase gradually based on the Newton’s Second law of motion:
So, the final (maximum) velocity of object in the end of ground will be:
But that will not happen in real life as a result of air friction effect which is alternatively called “Drag”. Then the Second law of Newton’s for motion will be:
The velocity will not increased for infinity. It will reach to a specific velocity called “Limit/Terminal velocity” which will not exceed it, due to the force equilibrium of gravity & drag force which will cancel the acceleration effect of gravity to be the net acceleration equal to zero.
The drag force may be calculated by:
The terminal velocity may be calculated by:
In the skydiving, human may reach to typical terminal velocity of 55 m/s (123 mph). Definitely there are many parameters governed the terminal speed according to previous equation .
Figure (141) – Skydiver
Now, let us imagine wildly this situation,
What will happen if we throw a light-weight wind turbine (500 Kg ) from a high altitude? Say as example altitude of 200m & after that we returned the turbine to its initial position as it shown in figure (142-A).
Figure (142) – New Design of wind turbine
To answer this question, we must find many important parameters such as final & average velocity, gravity & drag force & the output & returned power .
Assume that we have a design of wind turbine system as we see in figure (142-B) with these engineering specifications & environment factors:
Inner Radius of Frame = 1m
Outer Radius of Frame = 1.05m
Capacity factor (CP)/Efficiency of wind turbine = 45%
Coefficient of Drag in Frame = 0.5
Mass of turbine = 500 Kg
Density of air = 1.2 Kg/m3
Altitude of free fall = 200m
Now, let us play the physical game.
1) Gravity Effect
The gravity force may be calculated by:
The final (maximum) velocity of object (wind turbine) is;
We must find the average velocity to determine the output power of wind later.
As we see in figure (143) which is represent the graph of altitude-velocity curve in free fall (without considering the drag force).
Figure (143) – Curve Graph of Free Fall
If we calculate the area under the curve & divided it by the altitude, we will find the average velocity. Area of curve may be calculated precisely by integrating the equation (58).
Then we have equation (59) which represent the value of average velocity:
So, the average velocity will be 41.8 m/s. [Remember it ]
2) Drag Effect of Air
The area of frame will be evaluated by:
We will use the maximum velocity of free fall to see how much the maximum drag force may be exerted in the object, so:
The percentage of drag force in respect to gravity force is approximately equal to 7.72% ( 378.57/4910=0.0772) & the terminal velocity of object according to the equation  is:
We can neglect the effect of drag force in this example.
3) Output Power
The area of turbine (blades circle) can be calculated by:
The average output power will be evaluated based on the average velocity, so:
4) Recycling (Input) Power
The recycling power is terminology referred to the energy which is required to returned the wind turbine to its initial position (Altitude of free fall) per specific time.
We can use the conservative energy law of potential which is represent by equation:
So, for our example , the required energy will be:
Now let us determine the required time for returning the turbine to its initial position based on the time of free fall of object to reach the ground from 200m as altitude . We will use the average velocity, so the recycling time will equal the reaching time. The result is given by using equation :
(Note: Assume that we have two turbine, one for falling & other for returning in the same time)
The required power for returning will be:
As we notice, the power of recycling “returning” (P=204.8 KW) is greater than output power (P= 61.8).
So, is there any solution for this problem ?
Yes, by applying the concept of supply chains of Companies & factories as it shown in figure (144) which represent how we can recycle the wind turbines for free fall concept effectively.
Figure (144) – Supply Chains of Fallen Wind Turbines [Multi Units of Turbines]
We can decrease the return time of turbine to its initial position by increasing the units of turbine (N).
So, the power of returning of equation  will convert to:
Suppose that we have 5 turbine units, so the returning power will be:
That’s good result. The net power of system is:
The percentage/efficiency of net power in respect to the output power will be:
Table (1) shows the effect of increasing the number of units on the net power:
As we see in table (1), the net power & efficiency will increase by increasing the units of wind turbines.
We must deal with the problem of high kinetic energy when the turbine reach to the ground as it will create a strong crash.
There is 3 solutions for this critical situation:
- Using air/cotton bag in the ground to absorb the crash energy.
- Build a drag wings inside the turbine wind to decrease the velocity.
- Use a water pool, but we should note that the material of turbine not contain iron to prevent corrosion after period of time.
There is another solution but it is crazy.
If we can convert the velocity direction of turbine by 180⁰ as it shown in figure (145) by using strengthen wires, so we will catch the turbine in specific height with zero velocity according to the conservative energy law between the potential & kinetic energy.
By this crazy idea, we may decrease the returning time for units.
Figure (145) – Utilizing from Loss Kinetic Energy due to Free Fall
The success of this idea is depend on the light-weight of wind turbines.
Let us compare our new concept with traditional HAWT type.
The power of HAWT type for the same engineering specification (we will assume the average speed of wind equal to 6m/s) is:
The power of new idea is 41.3 KW, by using 10 unit only for recycling. Its amazing.
To make the same power by HAWT, we need to 229 HAWT units which has a radius of 1m.
Definitely, the construction cost of HAWT units will be more expensive compared to the new concept & that’s one advantage of the unique concept for producing electricity.
There are some notes which I like to discuss it with experts.
My first Note:
Why we don’t attach small wind turbine with planes in the end of it by using a connecting strengthened cord between the plane & turbine to produce electricity?
(Don’t tell me that it has relationship with drag force because I said small turbine, not large & it will be located after the tail of plane).
Figure (146) – Real Plane & Connected with Wind Turbine
We know that, the speed of planes may reach up to 900 Km/h (250 m/s).
Now imagine that we have a wind turbine with radius of 1m, then the output power will be:
It’s very high power which is produced by small radius of turbine.
So, there are two option to benefit from this massive power :
1) Either we use a large number of electrical storage batteries & after that we can discharge this power in electrical station near the airports. But the disadvantages of this idea is related with the massive mass of batteries which have a direct proportional relationship with fuel consumption of planes. So, we need to do feasibility study for such situation.
2) Or transmit the electricity wirelessly by using multi-electrical stations either on sky or land as we see in figure (147) & definitely it must be in fixed location to prevent any accidents between it & planes if we select the sky stations option.
Figure (147) – Air, Oceanic & Land Station for Wireless Electrical Transmission from Air Plane
There are a development technology of electrical transmission which used either microwaves or LASER beaming. It’s called generally “Wireless Power Transmission”.
Japanese scientist have succeeded in transmitting energy wirelessly, in a key step that could one day make solar power generation in space a possibility. Researchers used microwaves to deliver 1.8 Kilo-Watts of power – enough to run an electric kettle – through the air with pinpoint accuracy to a receiver 55 meters (170 feet) away. [Web-12]
Figure (148) – Transmission Electricity by LASER
Laser-Motive is American company which is developing wireless technology that delivers electricity via LASER beams. The scientists & engineers who run the company , Laser-Motive are using the lasers to power aerial drones but say their technology could also replace conventional power lines to deliver electricity to homes. [Web-13]
We may use this developed technology to transfer electricity from planes to the air/land/oceanic stations. If there are 100 planes fly in the sky in the same time, then the electrical power will be:
Definitely, this innovative idea will change the electrical industry of world but it depends on the number of planes which cross that country. We can construct the station in the roofs of houses, companies & institutions for receiving this free energy “Wind” as it shown in figure (149). The planes will acted as sun which is radiated it’s solar rays for growing the plants by photosynthetic process.
Figure (149) – Transmitting Electricity to Cities by Air Plane
If the above ideas is not logic, we have another idea related with hydrogen fuel industry.
We know that we can produce hydrogen from water by electrolysis effect by applying electricity voltage in the electrolysis cell, isn’t ?
The energy law for electrolysis cell is :
Δhf :The Enthalpy of Formation (KJ/mol).
ΔGf :The Gibbs Free Energy (KJ/mol0.
T: Absolute Temperature (K, Kelvin)
ΔS : The Entropy of Reaction (KJ/Kmol.K)
The enthalpy of formation is defined as the required energy to convert water/vapor to its basic chemical components (hydrogen & Oxygen). Using thermal, mechanical or electrical energy has not any effect in the enthalpy of formation value.
Gibbs free energy has a relation with the required electrical energy (if we are using electrolysis cell) to separate the water into hydrogen & oxygen, thus it doesn’t have a direct relationship with pressure variation. Gibbs free energy is represent the power which we (surrounding) give it to the system.
Equation (78) represent the energy law for electrolysis process in simple terms:
The standard entropy change at STP (Standard Temperature & Pressure) for those substances is given by (Ref-Thermodynamics- By: Yunus):
- Standard Entropy of Oxygen = 205 J/mol.K
- Standard Entropy of Hydrogen = 131 J/mol.K
- Standard Entropy of Vapor = 189 J/mol.K
- Standard Entropy of Water (Liquid) = 69.9 J/mol.K
- Enthalpy of Formation (water) = 285 KJ/mol
- Enthalpy of Formation (vapor) = 241 KJ/mol
Note: All these values are tabulated in thermodynamics & chemistry references.
Now, if we assume temperature is 25 ⁰ (298 k) for water (Liquid), so the required Gibbs energy (electrical energy) for producing 1 mol will be:
The required energy per mass of water is obtained by dividing the Gibbs free energy to the molar mass of water, so the density of energy is:
If you want to understand the electrolysis, you may read my detailed article to produce hydrogen by using Deep Water Technique here [Link]
The output electrical energy which is produced by one plane is depend on the flight period. Suppose that we want to know the energy for trip of 3 hours, so the energy may be calculated by:
The hydrogen mass production per trip will be:
Assume the price of hydrogen gas is 3.5 USD/Kg, so the sales per trip will be:
Tables (2) shows how much we will produce hydrogen fuel & the sales per day by increasing the number of planes (internal trips-inside the country) which is installed the small wind turbine.
Remember, that the mass production & sales of hydrogen fuel is achieved in one day. Multiply the value in 365 if you want to know how much will be achieved in a year.
What do you think now ?
Is it better to manufacture the plane for transporting passengers or producing hydrogen fuel?
Suppose that the trip ticket of 3 hours for one passenger will cost 300 USD & the weight of passenger is 90 Kg. So, the cost of ticket per mass of passengers will be 3.33 USD/Kg of passenger.
The ratio of sales to hydrogen mass = 3.5 USD/Kg
The ratio of ticket cost to passenger mass = 3.33 USD/Kg
What’s the economical view told us about previous comparison between passengers & hydrogen fuel ?
Ask yourself & don’t forget that we must consider the fixed & variable cost in our evaluation.
Figure (150) – Passengers Vs. Hydrogen Fuel
Remember the wind energy is renewable & free (there is no need for expensive concrete tower to hold large turbine of radius 30m).
My Second Note:
There is a new magnetic type for producing electricity without any displacement or rotational motion, named as “ Magnet-Striction” & it shown in figure (151) as sketch. The magnetic field changes for produce electricity by squeezing the middle alloys. This technology will lead to minimize the installation cost of mechanical parts & maintenance cost.
Figure (151) – Sketch of Magneto-Striction Material
Reverse magneto-striction has been identified in 1865 by the Italian physicist E. Villari, reverse magneto-striction is a property of some ferromagnetic materials in which applied changes in strain result in changes in the materials magnetic field.
Research on magnetic-restriction over the past 50 years has focused on the creation of increasingly powerful alloys for small-scale sensors, actuators and transducers. Unfortunately, these alloys have been too expensive and rare to work for power generation at any material scale.
iMECTM Technology platform has been found in 2009, Oscilla Power has pioneered the development of mechanical & electromagnetic systems that allows cost-effective, highly scalable magneto-strictive alloys to produce significant quantities of energy in specific environment. [Web-14]
You may watch the video of iMEC technology here [Link]
So, if we employ this promising technology in wind energy, it will be fantastic as it wants to be used for harvesting energy from ocean in project called “Triton” & figure (152) & (153) shows the small-scale experiment in University of Maine, USA .
Figure (152) – Small Scale Experiment of Triton System 1
Figure (153) – Small Scale Experiment of Triton System 2
The video of Triton project is here[Link]
Figure (154) & (154) shows the large scale of Triton project in ocean by Oscilla Power (Maybe photo was taken in 2016 as the article which is written in “digitalTrends.com website)
Figure (154) – Large Scale Experiment of Triton System 1
Figure (155) – Large Scale Experiment of Triton System 2
Triton is two-bodied wave energy device comprised of a surface float up top and a ring suspended in the ocean below. From above the device looks like a barge. From below, Triton looks like some kind of mechanical jellyfish. As the surface float undulates with the waves, the suspended ring resists that motion. This resistance generates energy. [Web-15]
So, we can benefit from the magnet-striction properties in the wind industry for producing electricity without any expensive movable parts (e.g. blades & rotor).
1) The pulley-motor system as we noticed previously is involved in many designs for increasing the power of wind turbine. Although it was drawn it as triangle shape to simplified our understanding, but in real life it must be in cone shape. So, we must thinking how we can design such device.
2) Making the device for converting of vortices to kinetic energy “fan”, is not very simple mission although we see that there are a Spanish tech startup has succeed to design the bladeless turbine by utilizing from vortices. Anyway, experiment must be made for install a small bladeless turbine near to the HAWT or convergence cone..
3) Many people complains against the installations of wind turbines as it will make a fatalities of birds. I agree with them but what’s the worst thing ?
Using fossil fuel which increasing the global warming. This will lead to increase the floods, tornado & hurricanes which definitely can kill thousands of animals, not only birds.
Figure (156) – Massive Tornado
That’s doesn’t mean we will stay watch without do anything towards this accidents of birds.
Any person will ask, why the manufacturer of wind turbines don’t built a cage around the turbine to prevent the birds or plastic bags to go through it ? Also in plane’s engines.
The reason has a relation with negative effect of viscosity on the speed of wind as it will reduce due to the friction.
So, what’s the solution ?
The solution is using temporary cage which it will attached with wind turbines as we see in figure (157).
Figure (157) – Automatic Cage/Curtin on the Wind Turbine
A sensor of motion will be placed in specific location to discover any birds near the wind turbines. When the bird be very close the critical zone, the movable cage will move similar to curtain for preventing the birds to go through the blades of turbine. The turbine will rotate but with efficiency due to the cage.
After a few seconds, birds will go away from the critical zone, then the sensor will give a signal to return the cage to its initial position & turbine will operate normally. There is no too much power has been lose in that few seconds.
1) There are many methods to increase the power of wind energy by utilizing from the indirect wind & we have made 5 new designs for generating electricity by utilizing from wind energy & I hope that it will see the light of life one day.
Utilizing from strong wind such as Hurricanes, Typhoons & Tornadoes for producing electricity will be great idea but it wants to understand the mechanism of that natural phenomenon to design a special turbine which can deal with it effectively. I will do that in the future.
Joke of people who believe that wind energy is free represented in funny photo of figure (158).
Figure (158) – Wind Energy is not Free Source of Energy (Lying)
1) Can We Rely on the Wind?
Wind generation is often described as intermittent, as the wind does not blow continuously. This is a misnomer as it implies an ‘all or nothing’ delivery of energy. An individual wind turbine will generate electricity for 70-85% of the time and its electricity output varies between zero and full output in accordance with the wind speed. However, the combined output of the UK’s entire wind power portfolio shows less variability, given the differences in wind speeds over the country as a whole.
Whilst the amount of wind generation varies, it rarely (if ever) goes completely to zero, nor to full output. In order to maintain security of supplies, a second-by second balance between generation and demand must be achieved. An excess of generation causes the system frequency to rise whilst an excess of demand causes the system frequency to fall. The electricity system is designed and operated in such a way as to cope with large and small fluctuations in supply and demand. No power station is totally reliable and demand is also uncertain.
Therefore, the system operator establishes reserves that provide a capability to achieve balance given the statistics of variations expected over different timescales. The variability of wind generation is but one component of the generation and demand variations that are considered when setting reserve levels. The GB System Operator, National Grid Transco stated in their.
Seven Year Statement that “based on recent analysis of the incidence and variation of wind speed we have found that the expected intermittency of wind does not pose such a major problem for stability and we are confident that this can be adequately managed”. [Ref-3]
2) In the end, did you think this design of wind turbine which is shown in figure (159) has any advantage or useful purposes?
Figure (159) – Can this Design Work Efficiently for Wind Energy Technology?
Thinking by yourself as I have sketched without any reason but intuitively.
I feeling it has some good concepts for energy & power industry.
Science reveals the darkness of ignorance & give you strong belief about the case which you decided to adopt it & share it with reasonable people.
Advanced Design of New Air Plane Powered Partially by Wind Power Technology
Thank for giving me your glory time to read my modest scientific post
Citations (References & Websites):
References & Articles [Ref-??]:
1) “Wind Power Fundamentals“, Presented by: Alex Kalmikov and Katherine Dykes With contributions from: Kathy Araujo PhD Candidates, MIT Mechanical Engineering, Engineering Systems and Urban Planning MIT Wind Energy Group & Renewable Energy Projects in Action.
2) ” Characteristics of Wind Power Systems“, Yahia Baghzouz, UNLV, Las Vegas, NV, USA
3) ” BWEA Briefing Sheet – Wind Turbine Technology ”
4) ” Wind Energy Technology, Current Status and R&D Future “, By: R. Thresher M. Robinson and National Renewable Energy Laboratory , P. Veers Sandia National Laboratories, Presented at the Physics of Sustainable Energy Conference, University of California at Berkeley, March 1–2, 2008
5) “Type of Wind Turbine“, (TeacherGeek.com)
6) ” Wind Energy Technology – THE FACTS PART I “, For more information on this, please visit the TPWind
7) ” Technical Introduction on Darrieus Wind Turbine “, Website: http://www.windturbine-analysis.netfirms.com/index-intro.htm
8) ” Introduction to Wind Power “, Alex Kalmikov, PhD, MIT Department of Earth, Atmospheric and Planetary Sciences (EAPS)
9) ” The Wind Energy (r)evolution: A Short Review of A Long History “, John K. Kaldellis*, D. Zafirakis – Lab of Soft Energy Applications & Environmental Protection, TEI of Piraeus, Greece
10) ” University Physics With Modern Physics“, Wolfgang Bauer &Gary D. Westfall.—1st ed. McGraw-Hill, a business unit of The McGraw-Hill Companies, Inc., 1221 Avenue of the Americas, New York, NY 10020. Copyright © 2011
11): ” CIVE2400 Fluid Mechanics- Section 1: Fluid Flow in Pipes”
12) ” Fluid Mechanics “, Jack P. Holman, Southern Methodist University John Lloyd, Michigan State University, McGraw-Hill Series in Mechanical Engineering – CONSULTING EDITORS
1) ” Wind Power ” – https://en.wikipedia.org/wiki/Wind_power
2) ” Lift & Drag ” – http://people.bu.edu/dew11/liftanddrag.html
3) ” Our Technology of Flo-Design ” – http://oginenergy.com/our-technology
4) ” Vortex Bladeless ” – https://en.m.wikipedia.org/wiki/vortex_bladeless
5) ” Quiet-Revolution Wind Turbine ” – https://en.m.wikipedia.org/wiki/Quietrevolution_wind_turbine
6) ” The qr6 Vertical Axis Wind Turbine ” – https://www.quitrevolution.com
7) ” Maglev vs. Other Turbines ” – http://www.solar.excluss.com/wind-power/magnetic-levitation-wind-tubine-versus-other-turbines.html
8) ” Vortex ” – https://en.m.wikipedia.org/wiki/vortex
10) ” Turbo-Charger ” – https://en.m.wikipedia.org/wiki/turbocharger
11) ” Linear Wind Generator ” – http://www.lineartechnologies.com.au
12) ” Wireless Energy by Japanese Scientists ” – https://lofi.phys.org/news/2015-03-japan-space-scientists-wireless-energy.html
13) ” Laser Beaming ” – https;//www.singularitweblog.com/lasermotive-laser-beaming/
14) ” iMEC Technology ” – https://oscillapower.com/imec-technology/
15 ” Triton Wave Energy Converter ” – https://www.digitaltrends.com/cool-tech/oscilla-power-triton-wave-energy-converter