WO2015155782A1

WO2015155782A1 - Vertical axis windmill

Info

Publication number: WO2015155782A1
Application number: PCT/IN2014/000383
Authority: WO
Inventors: Vedprakash NAITHANI
Original assignee: Naithani Vedprakash
Priority date: 2014-04-11
Filing date: 2014-06-04
Publication date: 2015-10-15
Also published as: IN2014MU01342A

Abstract

The present invention relates to a vertical axis windmill. More particularly, the present invention relates to a vertical axis windmill that includes a plurality of small size equally spaced blades are put alternatively, a plurality of Y-shaped joints and other embodiments as described herein after in this complete specification. The vertical axis windmill as disclosed in the present invention is of an improved and simplified construction that can be utilized both in urban and rural settings.

Description

VERTICAL AXIS WINDMILL

Field of the Invention

The present invention relates vertical axis wind mill, which use to generate the electricity by very low wind speed. The present invention doesn't require large height and can be installed at the rooftop and any other place with minimum space required and its environment friendly. In the present invention the blades are put alternatively and on the smaller size then the RPM and the Torque would be very good.

BACKGROUND OF THE INVENTION

As a result of the steadily increasing demand and cost of fossil fuels, and environmental factors related to the use of fossil fuels, the development of alternative and renewable energy sources is on the rise. Wind as a source of energy is a concept that has been promoted for some time. According, to one source, there is evidence which shows that windmills were in use in Babylon and in China as early as 2000 B.C. The U.S. Patent and Trademark Office have granted patents oil windmill devices dating back to the early to mid 1800's.

One area of particular attention is the conversion of wind energy into a useful form whether it is in the form of mechanical energy to drive a mechanical system such as a pump or in the form of electrical energy. Windmills have been used throughout the ages in converting wind energy into a useful form. Wind turbines usually take the form of horizontal axis wind turbines (HAWTs) and vertical axis wind turbines (VAWTs). By virtue of their vertical axes of rotation, VAWTs do not require alignment with the wind stream. In addition, drive train components can be located at ground level instead of being mounted higher above ground at HAWT rotor level. To overcome the limitation of horizontal axis wind turbines (HAWTs) the present invention for vertical axis wind turbines (VAWTs) has invented. VAWTs include drag-based designs and lift-based designs. U.S. Pat. No. 226,357 issued on Apr. 6, 1880 to Saccone describes an early,■ drag-based, vertical axis, windmill design. Designed over twenty years before the Wright brothers' flight, the windmill uses flat "fans" mounted pivotally on a support structure in order to catch the wind and cause the support structure to rotate. As the fans orbit the vertical axis, they pivot between a downwind orientation, in which each presents a broad profile in order to catch the wind, and an upwind orientation in which each presents a narrower profile for less drag. The windmill was designed without the benefit of aerodynamic design and performance theory. Operation is jerky, rough, and slow as the fans are continually pulled out of position by centrifugal force. The fans provide drive only intermittently during a somewhat small portion of each rotation. Upright bars at the outermost ends of the fans are highly disruptive to airflow. The system cannot achieve rotor speeds faster than wind speed.

U.S. Pat. No. 2,038,467 issued on Apr. 21, 1936 to ZonOski describes another vertical axis, drag-based, windmill design utilizing flat "vanes" on a rotatable frame. The two-phase vanes are better balanced. As they orbit the vertical axis,' they pivot about 170 degrees, or so, between ;a high-drag downwind orientation and a low-drag upwind orientation. Although the windmill shows potential for drag rotation over 180 degrees of each revolution, wind shadow and vane interference reduces overall effectiveness, and relative wind reduces the draft phase to less than 180 degrees. U.S. Pat. Nos. 4,408,956; 4,474,529; and U.S.' Pat. No. Des. 300,932 show other drag-based designs. U.S. Pat. No. 4,383,801 issued on May 17, 1983 to Pryor shows a lift- based VAWT. It includes vertically aligned airfoils mounted pivotally on a rotatable support. As the airfoils drive the support, they orbit the vertical axis. Meanwhile, a wind-vane-controlled pitch adjustment continually orients the airfoils relative to the wind direction. The machine detects wind direction by means of a vane and positions the controlling pitch flange accordingly. The mechanism is somewhat complicated, and positioning of the airfoils (angle of attack) is optimized only in the directly upwind and directly leeward positions; using crosswind lift force in both cases. In addition, FIGS. 8 through IT in the patent illustrate somewhat complex mechanisms for manipulating the airfoil shapes. The airfoils are underutilized during most of each rotation. The additional control appears to be an attempt to improve the efficiency of the machine. In a class of VAWTs called cycloturbincs. the pitch of the airfoils is controlled to create crosswind lift, but they must run at rotor speeds in excess of wind speed to be effective. They also frequently have difficulty self-starting. The windmill construction which has been most commonly utilized for the generation of electricity is a plural-bladed propeller positioned vertically for rotation about a horizontal axis. This type of construction has been widely used because, when positioned into the wind, the entire surface of each blade of the propeller is exposed to the full force of the moving air. The commercial windmill industry has developed around , the horizontal-axis construction and the aerodynamic principles and knowledge discovered in connection with atmospheric flight. Accordingly, it has become common practice to design such machines for the atmospheric/wind conditions of specific locations by varying the number and/or dimensions of the blades employed. The fewer the propeller blades, the more efficient the machines become at high wind speeds but the less efficient they are at lower wind speeds. .

Because the blades of horizontal-axis windmills are coupled indirectly to an electric generator which is effective only at a constant design speed, and because the blades themselves become unsafe at high speeds, the horizontal-axis windmills have been capable of utilizing only a small percentage of the theoretically-available power in the wind. The multi-blade windmills have high starting torque at low wind speeds, harvesting up to 30% of the kinetic energy from the wind but become very inefficient at high wind speeds. The Dutch 4- blade machines, for instance, utilize only about 16% of the winds' kinetic energy. The most common and efficient windmills today are of the two and three blade types designed for high tip speed operation. These machines harvest roughly 42% of the theoretical 59.2% kinetic energy from the wind. Such windmills operate within a narrow window or range of wind velocities defined by a cut-in wind speed of 3-5 mps (meters/sec.) and a cut-out wind speed of about 25 mps. To maintain a near constant level of torque to drive the generator has required either: complex controls, in the case of pitch control, or intricate blade designs, in the case of stall control, both of which are expensive to build and maintain. In addition, such wind machines require yaw mechanisms with motors, gearboxes, cable twist counters, etc. to keep the machine yawed against the wind. These requirements have combined to make the horizontal-axis windmills economically unattractive except in areas where alternative forms of electricity generation are not readily available.

Today's windmill designs also have other drawbacks. They have problems with gyroscopic vibration when the machine veers with changing wind direction, They are vulnerable to high bending moments at the base or root of the blades as each blade passes by Or into the wind-shade of the supporting mast as well as when being braked during tempest conditions. These bending moments lead to frequent blade replacements and high maintenance costs. Because of their massive structures, these machines, of necessity, are remotely located miles from the area of power usage, thus necessitating construction of expensive power grids to transport the energy produced to the point of consumption, (generally large cities). Consequently, an approximate eight to ten percent of the power generated never reaches its destination due to line and transformer losses. Lastly, because of opposition from environmental lists with regard to the esthetics in natural settings as well as prohibition from municipal regulating authorities due to safety hazards associated with these large-prop machines in populated areas, many areas which would be ideal for generating wind energy, such as atop large buildings, are simply off-limits due to opposing design constraints. The safety factor with efficient turbines becomes significant for higher wind speeds. Special precautions need to be taken to prevent the disastrous accidents which have occurred with windmills and known turbines in storm or hurricane force winds. In summary, the factors which should be considered in the provision of a commercially viable windmill are: (1) the need to react to the wind over a wide range of wind speeds with a substantially constant power output; (2) the need to react to the wind regardless of direction so avoiding continual re-orientation to ensure that the windmill always points into the wind; (3) the need to reduce manufacturing costs and increase power output efficiency; (4) the need to be self-starting; and (5) the need to reduce excessive stresses generated in the structure at high wind speeds.

Accordingly, there is a need for a vertical axis windmill of an improved and simplified construction that can be utilized both in urban and rural settings, that does not depend upon wind direction or wind velocity for optimal energy production, and that utilizes the back pressure during the remaining half of a rotation cycle to apply a breaking force to the rotor of the turbine to prevent over speed, while overcoming the drawbacks of prior vertical axis windmill or wind turbine.

Moreover due to problem of longer height of the blade it is very inconvenient to install the wind mill and so in the present invention the blades smaller size so, we made the smaller size of the blades and used one distance piece to install another set of blades in the windmill. In the present invention smaller size blades are placed alternatively and each blade gets more wind and thus more RPM.

OBJECTS OP THE INVENTION ; The main object of the present invention is to obviate the above mentioned prior-art problems.

It is an object to provide efficient, long life, low maintenance, easily installable and safe windmill in which smaller size blades are arranged alternatively vertical to the ground.

It is yet the other object of the invention to provide vertical axis windmill which can be installed any places like roof tops, office building, farm houses, resorts etc.

After installing this system the RPM increased by more then 15% and thus energy by another 10% installation has become very easy. In the present invention the blades are put alternatively and on the smaller size then the RPM and the Torque would be very good.

SUMMARY OF THE INVENTION

The present invention is directed to a vertical axis windmill including a plurality of equally spaced small size blades. Each of the blades is put alternatively for rote able around the rotor shaft which is vertical to the ground. Each blade has a top, a bottom, leading edge onto top and trailing edge onto the bottom. Further, each blade has a top edge lip onto the top of the blade and bottom edge lip onto the bottom side of the blade. In the present invention the blades are put alternatively and on the smaller size then the RPM and the Torque would be very good.

In the present invented vertical axis wind turbine to generate the electricity by very low wind speed. In the present invention, heights of the wind mill are small so, these types of wind mill are installed at the rooftop and other place with minimum space requirement. Moreover in the present invention system, the blades are put alternatively and on the smaller size then the RPM and the Torque would be very good. And the installation in also become very convenient so in the present invention the smaller size of the blades and used one Distance piece to install another Set of Blades in the wind Mill. These blades instead of 5 are now 10 and put it in a way that the every blade is placed alternatively and each blade gets more wind and thus more RPM. After installing this system we found the RPM increased by more then 15% and thus energy by another 10%. installation has become very easy; ·· - .. ·^{■'■ ■} . ·^{■ ■} Each blade is supported with a Y-shaped joint at the top and at the bottom by an arm or other structure wherein Y-shaped joint is fixed onto the rotor shaft. The top side of the blade of the Y-shaped joint is larger than the bottom side of the blade of the Y-shaped joint. Each blade is secured to the blade attachment rods attached with the distance joint wherein blade is attached with the top side of the distance joint while the bottom of the distance joint is fixed onto the rotor shaft.

Further, the blade attachment rods axe fixed with the blades just above the fixation point of Y-shaped joint with each of the blade. A generator is fixed onto the rotor shaft wherein the generator is made on the principal of flywheel so that once it starts rotating it would not stop immediately if the wind stops. This generator is attached to the blades for the rotation and to its shaft for the proper torque. A plurality of stabilizing arm is fixed around the blades from the outer side of the blades. Stabilizing arm is round or hexagon in shape. In case if two stabilizing arms are used, they are fixed at a distance so that the lift of the blades may kept in control even in the high speed of wind and due to this effect it is possible to make a good balance and stabilization of the windmill while in the working condition. For example: the distance of the fixation between two stabilizing arms are kept in a manner so that equal margin from the leading edge of the top and from the trailing edge of the bottom side of the blades from the fixation of the stabilizing arms may be left. There has thus been outlined, rather broadly, the more important features of the invention in order that the detailed description thereof that follows may be better understood and in order that the present contribution to the art may be better appreciated. Numerous objects, features and advantages of the present invention will be readily apparent to those of ordinary skill in the art upon a reading of the following detailed description of presently preferred, but nonetheless illustrative, embodiments of the present invention whe taken in conjunction with the accompanying drawings. The invention is capable of other embodiments and- of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of descriptions and should not be regarded as limiting.

As such, those skilled in the art will appreciate that the conception, upon which this disclosure is based, may readily be utilized as a basis for the designing of other structures, methods and systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention. For a better -understanding of the invention, its operating advantages and the specific objects attained by its uses, reference should be had to the accompanying drawings and descriptive matter in which there is illustrated the preferred embodiments of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS It will be convenient to further describe the present invention with respect to the accompanying drawings that illustrate possible arrangements of the invention. Other arrangements of the invention are possible, and consequently the particularity of the accompanying drawings is not intended to be limiting of the present invention.

FIG. 1 represents the front view of the vertical axis windmill constructed in accordance with the principles of the present invention;

FIG. 1(A) represents the top view of the vertical windmill

FIG. 1(B) represents the air flow and rotation of the windmill from the front view the vertical axis windmill

FIG. 2 represents the perspective view of a vertical axis windmill and air flow.

FIG. 2(A) represents the top view of a blade

FIG, 2(B) represents the air flow passed through the blade

FIG 3 represents the view of Y-shaped joint- FIG. 4 represents the top view of a distance joint along with the blade attachment rod

FIG. 4(A) represents the front view of a distance joint without the blade attachment rod

Detailed description of the invention

Before explaining the present invention in detail, it is to be understood that the invention is not limited in its application to the details of the construction and arrangement of parts illustrated in the accompanying drawings. The invention is capable of other embodiments, as depicted in different figures as described above and of being practiced or carried out in a variety of ways. It is to be understood that the phraseology and terminology employed herein is for the purpose of description and not of limitation.

According to the present invention, the vertical axis windmill comprises:

a foundation(lOl) on which the pole(102) is fixed; a pole(102) on which the dual rotor shaft(103) are attached wherein the each rotor shaft(103) are connected through the distance joint (106) and engaged with an electric generator(104). A plurality of blades(105) are arranged alternatively spaced from and rotate able around a each rotor shaft(103) vertical to ground; each said blade(105) having a top(105- a), a bottom( 105-b), leading edge onto top (105-c) and trailing edge onto the bottom(105-d), wherein each blade has a top edge lip (105- aa) onto the top of the blade and bottom edge lip( 105-bb) onto the bottom side of the blade; a distance joint(106) of which the bottom side(106-b) is attached to the rotor shaft(103) and the top side(106-a) is fixed with the plurality of blades(105) using plurality of blade attachment rods (107); a plurality of Y-shaped joint( 108) wherein one side of the Y-shaped joint(108-a) is attached to the upper side of the blade(105-a) and bottom side of the Y-joint (108-b) is attached to the lower side of the blade(l 05-b) and the end of the Y-shaped joint(108- c) is attached to the rotor shaft(103); A plurality of stabilizing arm(109) is fixed around the blades from the outer side of the blades wherein stabilizing arm is fixed at a distance so that the speed of the rotating blades may kept in control even if the speed of the wind is higher than the desired speed of power generation. FIG. 1 shows a front view of the vertical axis windmill constructed in accordance with the principles of the present invention, FIG. 1(A) shows a top view of the vertical axis windmill and FIG. 1(B) is air flow and rotation of the windmill from the front view the vertical axis windmill.

FIG. 2 shows a perspective view of a blade, FIG. 2(A) shows a top view of a blade and FIG. 2(B) shows air flow passed through the blade. Now referring to the drawings of Fig 1, 1(A), 1(B), 2, 2(A) & 2(B): The present invention is directed to a vertical axis windmill including a plurality of small size equally spaced blades (105). Each of the blades are put alternatively of rotable around the rotor shaft (103) which is vertical to the ground. Each blade (105) has a top (105-a), a bottom (105-b), leading edge (105-c) onto top and trailing edge (105-d) onto the bottom. Further, each blade has a top edge lip (105-aa) onto the top of the blade and bottom edge lip(105-bb) onto the bottom side of the blade.

The blades (105) are made of fiber reinforced plastic (FRP) and blades are given a specific aerodynamic design so as to utilize the kinetic energy of the wind to the fullest. Further, the aerodynamic design of a blade helps the blades to move in the direction of the wind and do not interfere in the opposite direction of the wind which makes the rotation of the blades in a one direction better. The Aerodynamic design is also made that the air pushes the blade from both the side means- the inside of the blade and the outside of the blade also. The inside air is circulated and gives fast momentum to the blades.

Further, the height, weight and number of blades are varied and dependent on the requirement of the conversion of the kinetic energy into electrical energy.

In general, these heights of the blades are divided in two part so instead of 5 or 7 or 9 blades now 10 or 14 or 18 blades are put it in a way that the every blade is placed alternatively and each blade gets more wind and thus more RPM. After installing this system we found the RPM increased by more then 15% and thus energy by another 10%.installation has become very easy.

Further, FIG. 1 shows a front view of the vertical axis windmill constructed in accordance with the principles of the present invention, FIG. 1(A) shows a top view of the vertical axis windmill, FIG 3 shows a view of Y-shaped joint( 108),

FIG. 4 is a top view of a distance joint (106-a) along with the blade attachment rod (107) and FIG. 4(A) is a front view of a distance joint (106) without the blade attachment rod (107.).

Now referring to the drawing of Fig 1, 1(A), 3, 4 66 4(A), the construction of the vertical axis windmill is provided as follows:

A plurality of Y-shaped joint (108) has been used in the present invention wherein one side of the Y-shaped joint (108-a) is attached to the upper side of the blade (105-a) and bottom side of the Y-joint (108-b) is attached to the lower side of the blade (105-b) and the end of the Y-shaped joint(108-c) is attached to the rotor shaft(103). Further, the number of the Y-shaped joint (108) used in the construction of Windmill is identical to the blades (105) used in construction of the windmill. Necessarily, the upper side of the blade (105-a) of the Y-shaped joint is larger than the lower side of the blade (105-b) of the Y-shaped joint. Y-shaped joint (108) is made from any metal selected from the hard metal like stainless steel, iron or cast iron or the like. The fixation of the Y-shaped joint (108) with each of the blade is done using any conventional method for example using nuts and bolts or using brackets and the like.

The main advantage of the use of the Y-shaped joint(108) is that it gives durability to the blades(105) and thus gives the stability to the windmill itself and plays an important role to keep the Wind mill safe and under working conditions in hurricane or tornado. Further, Y- shaped joint (108) give equal weight on the windmill as well as offer better torque.

A plurality of blade attachment rod (107) is provided onto the distance joint (106). In general, the number of the blade attachment rod (107) is identical to the blades (105) used in construction of the windmill. Each blade (105) is secured to the blade attachment rod (107) attached with the distance joint wherein blade(105) is attached with the top side of the distance joint(106-a) while the bottom of the distance joint (106-b) is fixed onto the rotor shaft (103). Further, the blade attachment rods (106) are fixed with the blades (105) just above the fixation point of Y-shaped joint (108) with each of the blade (105).Blade attachment rod (107) and distance joint (106) are made from any metal selected from the hard metal like stainless steel, iron or cast iron or the like. The fixation of the blade attachment rod (107) with distance joint (107) and with the blade (105) is done using any conventional method for example using nuts and bolts or using brackets and the like.

The main advantage of the use of the blade attachment rod (107) fixed onto the distance joint (106) is that it gives strength and durability to the blades (105) and thus gives the stability to the windmill itself.

A rotor -shaft (103) is engaged with an electric generator (104) wherein the generator (104) is made on the principal of flywheel so that once it starts rotating it would not stop immediately if the wind stops. This generator is attached to the blades for the rotation and to its shaft for the proper torque.

A plurality of stabilizing arm (109) is fixed around the blades (105) from the outer side of the blades. Stabilizing arm (109) is round or hexagon in shape. In case if two stabilizing arms (109). are used, they are fixed at a distance so that the speed of the blades( 105) rotation may kept in control even at a high speed of wind than the desirous speed of power generation and due to this effect it is possible to make a good balance and stabilization of the windmill during its working. For example: the stabilizing arms fixation distance between 2 stabilizing arms (109-a & 109-b) are kept in a manner so that equal margin from the leading edge of the top and from the trailing edge of the bottom side of the blades from the fixation of the stabilizing arms may be left. Stabilizing arm(109) is made from fiber reinforced plastic (FRP) or from a durable and hard metal selected from like stainless steel, iron or cast iron or the like. Each stabilizing arm is fixed to the blade (109) using any conventional method for example using nuts and bolts or using brackets and the like.

Optionally, a foundation (101) is provided on which a pole (102) is fixed wherein pole(102) is used to affix the vertical axis windmill as shown in figure 1 and described in the aforesaid paragraphs.

Once the kinetic energy is converted into the electrical energy, electrical energy may get stored and then utilizes for the suitable purposes. For example, there is provided a charge controller (HO) and a battery for a purpose of storing the converted energy from kinetic to electrical energy. An electric generator (104) fixed to the rotor shaft (103) converts the kinetic energy produced through the rotation of the blades(105) into the electrical energy which is further stored into the battery 1 1) using the charge controller(l 10). Thus the specific design of the windmill of the present invention is compact and quiet making it suitable and desirable for use in urban settings, where the windmill may be installed on to the roof tops. It is also useful if installed on to the open space, on the sea shore, onto the mountain or the like.

EXPERIMENTAL PART OF THE INVENTION In general, the vertical axis wind mill of the present invention works even at a very low wind circulation.

For example: The windmill of the present invention starts generating the power at a very low wind speed of 1.5 meter/sec and when the speed reaches 4 meter/sec it generates almost 12 % of the rated windmill (lkw of electrical energy). At one particular time it was found that when speed reaches 7 meter/sec, the wind mill has generated 700 watts of electrical energy which is almost 70% of windmill electrical energy production capacity.

Aerodynamic design of the blade(105), durability and stability given by Y-shaped joint( 108) & stabilizing arm(109), an electrical generator ( 104) engaged with rotor shaft (103) and charge controlled 1 1 1) makes the invention workable and thus the present invention fulfill the below criteria:

• Ability to react to the wind over a wide range of wind speeds with a substantially constant power output and ability to react to the wind regardless of direction so avoiding continual re-orientation to ensure that the windmill always points into the wind;

• reduces manufacturing costs and increase power output efficiency;

• self-starting; and ^• "reduces excessive stresses generated in the structure at high wind speeds.

While, the invention has been described with respect to the given embodiment, it will be appreciated that many variations, modifications and other applications of the invention may be made. However, it is to be expressly understood that such modifications and adaptations are within the scope of the present invention, as set forth in the following claims.

Claims

VERTICAL AXIS WINDMILL consisting with a

foundational), pole (102), dual rotor shaft (103), electrical generator (104), a plurality of blades (105), distance joint (106), attachment rods (107), a plurality of Y shaped joint (108), stabilizing arm (109), charge controller (110), a battery(lll), wherein pole (102) is fixed on foundation (101) on which the dual rotor shaft (103) are attached wherein the each rotor shaft (103) are engaged with an electric generator (104); wherein each rotor shaft (103) is connected by distance joint (106); wherein a plurality of blades (105) are put alternatively rotable around the rotor shaft (103) which is vertical to the ground; wherein the p rality of stabilizing arm(109) is fixed around the blades from the outer side of the blades wherein stabilizing arm is fixed at a distance so that the speed of the rotating blades may kept in control even if the speed of the wind is higher than the desired speed of power generation.

A vertical axis windmill as claimed in claim 1 wherein the number of blades(105) are arranged alternatively from 10 blades or 14 blades or 18 blades and dependent on the requirement of production of electrical energy.

A vertical axis windmill as claimed in claim 1 wherein each said blade(105) having a top(105-a), a bottom (105-b), leading edge onto top (105-c) and trailing edge onto the bottom(105- d), wherein each blade has a top edge lip (105-aa) onto the top of the blade and bottom edge lip( 105-bb) onto the bottom side of the blade. A vertical axis windmill as claimed in claim 1 wherein a distance joint(106) of which the bottom side(106-b) is attached to the rotor shaft(103) and the top side(106-a) is fixed with the plurality of blades (105) using plurality of blade attachment rods (107).

A vertical axis windmill as claimed in claim 1 wherein a plurality of Y-shaped joint( 108) wherein one side of the Y- shaped joint(108-a) is attached to the upper side of the blade(105-a) and bottom side of the Y-joint (108-b) is attached to the lower side of the blade(105-b) and the end of the Y- shaped joint( 108-c) is attached to the rotor shaft (103).

A vertical axis windmill as claimed in claim 1 wherein number of blade attachment rods(107) used is identical to the blades(105) used in the vertical axis windmill.

A vertical axis windmill as claimed in claim 1 wherein number of Y-shaped joint (108) used is identical to the blades (105) used in the vertical axis windmill.

A vertical axis windmill as claimed in claim 1 wherein number of stabilizing arm (109) is dependent on number of blades(105) and weight and height of the blades.

A vertical axis windmill as claimed in claim 1 further electric generator (104) fixed to the rotor shaft (103) converts the kinetic energy produced through the rotation of the blades(105) into the electrical energy which is further stored into the battery(l 11) using the charge controller^! 10). A vertical axis windmill as claimed in claim 1 further comprises: a charge controller (110) and a battery (111) to store the converted kinetic energy into electrical energy.