|Title of Invention||
|Abstract||A windmill generator for collecting and converting wind energy into electrical energy comprising of a annular shaft mounted on a supporting structure/platform, rotor blades (2) mounted on the said shaft (3) and at the smaller end of a duct (1) of metal or cloth in conical, rectangular or cylindrical shape having larger cross-section at one end and smaller cross-section on the other and a shutter(9) at the larger end of the duct for changing the velocity of air manually as well as automatically. The rotor blades convert wind energy into rotational mechanical energy for both horizontal as well as vertical shaft turbine for effective alternate power source in any wind condition/ any direction of wind. The flywheel (5) of heavy mass and weight on the outer circumference away from the center provides high moment of inertia to keep the speed of the main shaft constant in any condition by storing rotational kinetic energy (Iw2) in it. (Where I is the moment of inertia of the flywheel & w is the angular velocity of the shaft). The generator (4) coupled to the main shaft either through coupling or through direct mounting converts the rotational energy into electrical energy.|
|Full Text||WINDMILL GENERATOR
Electrical energy is converted from different sources of energy such as chemical energy [dry cell, etc.], thermal energy [coal, wood etc.], nuclear energy [uranium- 235, etc.], ocean waves, hydro power plant [water at a height], wind energy etc. Electrical energy derived from wind energy has a little share of the total electrical energy produced in the world. There are many designs proposed by different researchers on windmill turbine & generator.
There have been many wind energy collection methods and devices proposed in the past. Classic windmills and turbines employ blade surfaces to engage a wind stream and convert the energy in the wind stream into angular force, which rotates a horizontal shaft. Such windmills with their exposed rotating blades, pose technical as well as safety, environmental, and aesthetic concerns, which limit their use. The rotor blades of such windmill turbines travel at high rates of speed and can endanger people on the ground. Vertical axis turbines, which are more recent, address many of the shortcomings of the horizontal shaft devices but have their own inherent problems, as they are large, employing towers hundreds of feet in the air. They are expensive and have significant aesthetic impact. At present the windmills are huge,
difficult to install expensive to maintain, repair and cause noise pollution.
The kinetic energy in the wind is l/2 v2 per unit mass or 1/2 gv2 per unit volume, if the speed of the wind is v & g is density of the wind. When wind is allowed to strike on the blades, then the wind energy is converted into rotational mechanical energy, which is further converted into electrical energy. The force on the disc of the rotor is equal to [pu - pd ] A , where A is the area of the blades. Finally, the output power of a windmill can be given as
P = gA[V+Vw][V2-Vw2]
Where V, is wind velocity before striking on the disc of blades &VW, is the wind velocity after striking on the disc of blades.
If Vw =V/3 Then above equation is given as
This means output power is directly proportional to the area of disc of the rotor blades & Cube of wind speed. Larger the area of disc of rotor means large size of the overall machine which results to a very high cost of the machine.
STATEMENT OF INVENTION
Accordingly there is provided a windmill generator for collecting and converting wind energy into electrical energy comprising of a shaft mounted on a supporting structure/platform with a flywheel fixed onto the shaft; a generator connected to the shaft and characterized by duct of metal or cloth in conical shape having large cross-section at one end and smaller cross-section at the other end; rotor blades mounted on an annular shaft at the smaller end of the duct of metal or cloth; shutters fixed at the larger cross section end of the duct; windmill mounted on a rotatable stand to align the air inlet according to the direction of the wind for optimal results.
SUMMARY OF THE INVENTION
Thus, the aim of the present invention is to overcome the above-mentioned drawbacks. The present invention is designed to employ as a cost effective alternate power source in any wind form-a breeze, storm, and high wind velocity. The aim of the invention is to provide a windmill generator which has a high degree of efficiency and is simple in construction, simple to install, easy to operate, and which can be combined with already existing wind driven device. It is possible to extend it as required without great financial & technical outlay.
In the present invention, the turbine converts wind energy into rotational mechanical energy for both horizontal as well as vertical shaft turbine. The present invention more specifically relates to wind generator turbines both vertical as well as horizontal designed to be employed as a cost effective alternate power source in any wind condition/any direction of wind. In all prior designs for a given cross-section area of the disc of the blades, the output of the machine depends only on the velocity of air, which changes the output of the machine. However I this invention, a shutter has been provided in the system, which can change the velocity of air manually as well as automatically. This mean it is possible to change the output of the machine for a given speed of the wind, which is not possible in prior designs. Also the complete generator, blades, & shaft can be protected
from rain, water, moisture like climate etc by providing cover, which will increase the life of the machine.
The rotor, which rotates in the horizontal direction, has optimum
aerodynamic characteristics in order to minimize the air resistance of
the air. The air is allowed to compress before it strikes on the blades
there is increase in velocity of air & decrease in pressure before the
disc of the blades. Then further the air is allowed to expand after
striking on the blades leading to further decrease in pressure behind
the blades, which will result to large amount of energy transformation.
This effect will also decrease the static pressure on the blades. The
blades used in this system may be fixed at a particular angle or
movable blades can be used with the help of servomechanism, thus
providing many options. The whole machine can be mounted on a
rotatable stand to alignment according to the direction so that the air
inlet is aligned optimally against the wind direction.
If the wind velocity is increased then the output power will increase exponentially & the size of the machine required will be small. To increase the structural integrity, the torque generating elements, namely the rotor blades are directly attached to the main shaft rather than attached to the gearbox etc. Thus, the torque forces generated can be transferred to the shaft directly & further transferred to electrical
generator without any loss. In addition, by providing a shutter in the machine, the cross sectional of the duct can also be changed to regulate the output power. Therefore, in the present invention both the cross section area as well as the velocity of wind can be changed and hence obtain different power output at a given speed of the wind.
In a further embodiment the pairing is aligned by a servomotor, which
is controlled by a wind sensor. The windmill generator consists of an
annular main shaft, along with the rotor blades, which rotates in the
horizontal direction in the present invention. The windmill also
includes annular bearings, & the main shaft rotates in these bearings;
the outer race of these bearings is fixed in the housings, which are
further fixed upon the structure. These bearings offer very low friction
to main shaft, which result into high efficiency of the machine. This
invention has a single shaft for wind turbine, generator, & flywheel so
loss in this machine is negligible as compared to all earlier designs. In
this invention there is neither any gearbox nor belt / pulley
arrangement and hence there is no wear & tear losses in the machine,
which provides a simple structure of the machine. As there is no
gearbox, pulley, & belt arrangement this means no oil will be used, so
there is no noise pollution, air & oil pollution. This design is
completely environmental friendly. The windmill generator herein is a
lightweight and simple structure, which can be assembled, maintained,
shifted easily and is affordable by common man. the initial as weii as running cost per watt of the windmill generator would be comparatively less that other windmills.
The present invention meets the economic as well as environment concerns that require windmills not only to light weight, inexpensive, easy to install, repair and maintain but also there is no noise or oil /air pollution.
BRIEF DESCRIPION OF DRAWINGS
A brief description with reference to the drawings, in which: FIG-1 [a] shows conventional windmill generator converting wind energy into electrical energy with a rotor rotating vertically about a horizontal axis. This wind generator shows blades, tower, gearbox etc. FIG-1 [b] shows the side view of the wind generator. FIG [c] shows the powerhouse building.
FIG-2 shows the side view of the duct, which is used in this invention, having a large cross section area on one side & a smaller cross section area on the other. This duct will be helpful in increasing the velocity of the wind.
FIG-3 shows the complete view of the present invention, a horizontal shaft type machine, which consists of a duct having large cross section area from where air is allowed to enter & small cross section area from where air is just ready to strike the blades. Due to this the speed of the air increases, as the discharge remains constant throughout the tube as per Bernoulli's principle. This also shows the main shaft, blades, generator, flywheel, & supporting structures etc.
FIG-4 shows the flywheel, as a heavy mass on the outer circumference away from the center, which will give high moment of inertia, to keep the speed of the main shaft constant in any condition. It stores rotational kinetic energy in it while in motion in normal condition in the system.
FIG-5 shows an over all view of a vertical shaft windmill system under the present invention which is able to produce electrical energy. This system may be used for the production of large size of windmill machine.
FIG-6 shows how the wind streams flow before & after the striking the disc of the rotor in the already existing windmill machine. FIG-7 shows how the wind streams flow before &, after the striking the disc of the rotor for present invention for windmill machine.
FIG-8 shows the side view for the shutter, which will be used in this invention, & would be helpful for the safety of the machine during high wind velocity as well as to regulate the output of the machine.
DESCRIPTION OF PREFERRED EMBODIMENTS The present invention provides the methods and a system /device to produce electrical energy from wind energy. The key aspects of this invention are that the parts of the invention collect energy from the wind with high efficiency.
FIG-1 shows the conventional windmill machine system. When wind strikes on the large size blades (11), wind energy applies a force on the blades; depending upon the angle of the blades. This force rotates the shaft (12), which is further coupled with the electrical generator. (14)
In this preferred embodiment an energy system design comprises a duct (l).As illustrated in detail in FIG-2 Duct (1) is made of metal, cloth, etc. where the cross section area from where the wind allowed to enter (Ai) is larger as compared to the cross section area near the blades (A2). As the cross section area decreases the velocity of air will be increased. The discharge [velocity of the fluid x cross section area of the tube/ or any object] remains constant throughout the duct as per Bernoulli's effect. The product of the air's velocity and cross section
area at the entrance point of the duct and end point of the duct remain constant. This effect will increase the velocity of the air, as the cross section area at the end of the duct is small as compared to that of the entrance point. Therefore, the velocity of the air is far greater near the blades and less pressure exists near the blades as compared to the pressure at the entrance point of the duct. As air is allowed to expand after striking the blades, it will further drop the air pressure as well as decrease the velocity of air- this means large amount of wind energy transferred in to rotational mechanical energy takes place, which was not possible in all prior designs. Moreover, in the present invention more the energy transfer more will be the output of the machine. This will also reduce the static pressure around the blades (2), which causes the opposite direction of rotation of the blades motion hi the conventional windmill machine. The blades are mounted on the main shaft (3) at a fixed angle hi such a way to get maximum output. When air strikes on the blade (2), the shape of the blade is such that one side is concave & the other side is convex type. Air passing around the blade creates less pressure on the convex side, which results into a force, which will act on the blade from convex to concave direction. Thus blades convert wind energy in to rotational mechanical energy. The electrical generator (4) is coupled to the main shaft either through coupling or through mounting on the main shaft (3). The electrical generator (4) converts the rotational mechanical energy into electrical
energy. An important part of the present invention is flywheel (5)
which has heavy mass on the outer circumference away from the
center to provide moment of inertia. This flywheel (5) plays an
important role in storing rotational kinetic energy hi it, which is equal
to Iw2.1 is the moment of inertia of the flywheel (5) & w is the angular
velocity. The flywheel (5) absorbs extra energy if there is sudden
increase in wind velocity and when there is sudden decrease in the
velocity, then the flywheel (5) will provide the extra energy stored hi it
to the system so that the angular speed of the shaft (3) remains
constant. Thus flywheel (5) provides stability to the system. The whole
structure (6) is mounted on the supports and platform. To eliminate the
friction, numbers of bearings (7) for the main shaft (3) are used. This
will increase the efficiency of the machine.
FIG -4 shows the flywheel (5) having heavy mass on the outer circumference away from the center to provide moment of inertia.
FIG-5 shows the windmill system with vertical shaft arrangement. Here duct (31) is used as shown in FIG-5 having one inlet but two outlets, to provide a balanced force on the main shaft (36). In this system blower type multi blades (32) arrangement is u$ed. The electrical generator (33) converts rotational mechanical energy into electrical energy. The flywheel (37) provides the system stability as in
horizontal shaft system. The guide bearing (34) provides the alignment to main shaft (36). RCC structure (38) provides the support to all the moving parts of this system. Thrust bearing (40) bears the total load of the movable parts. A movable structure (39) provides support to duct (31) so that the direction of the duct can be changed with change in direction of wind. The above system is suitable for large rating of machines.
FIG-6 & FIG-7 show the flow of wind streams in conventional windmill turbine & in the present invention respectively. In FIG-6 it is clear that in conventional windmill turbine there is high pressure around the disc of the rotor as there is no separation of wind streams R & S, which increases the static pressure around the disc of rotor (9). So there is very little difference in pressure P1 & P2, as shown in FIG-6.
Where as in FIG-7 in respect of the present invention a duct(l) (3 l) is provided, where the area of cross section at the inlet is large & smaller at the outlet, separating the wind streams 'S'- one that moves in side the duct and 'R'- that flows out side the duct. This means that after striking on the blades wind stream 'S' tries to expand & again after some time gets parallel to the stream 'R'. And hence static pressure around the disc of rotor (9) is negligible. There is large difference in pressure P1 & P2 in present invention.
FIG-8 shows the side view of the shutter (9). which is helpful to regulate the output of the machine & protect the whole machine [turbine, generator, main shaft etc.] from very high wind velocity and storm.
The shutter (9) provides a rectangular plate (10A) at lower side, which opens /closes the shutter plates (10) in such-a way so that the required output of the machine can be achieved. During high wind velocity this rectangular plate (10A) moves in the direction of wind and closes the shutter plates (10) according to the requirement automatically. If there is a storm then the rectangle plate (10A) moves in such a way that the shutter (9) is completely closed, to ensure the safety of the machine.
FIG-9 shows the comparison of output power between conventional machine & new invented machine system. Here we assume a conventional machine whose area of disc of rotor is 4 square meters & new invented machine system whose area of cross section of the duct is 4 square meters at inlet side & one square meter at the outlet side of the duct. Area of disc of rotor is one square meter. The chart shows clearly the difference that the output of the new invented system is very large as compared to the conventional machine. Secondly, the
wind velocity increases the output of the new invented machine exponentially, where as in the conventional machine- rise of output is very less.
Many modifications and variations of the present invention are possible in light of the above. It is therefore to be understood that, within the scope of the appended claims, the invention may be practiced other than as specifically described.
1. A windmill generator for collecting and converting wind energy into electrical energy
comprising of a shaft mounted on a supporting structure/platform with a flywheel fixed
onto the shaft; a generator connected to the shaft and characterized by (a) duct of metal
or cloth in conical shape having large cross-section at one end and smaller cross-section
at the other end; (b) rotor blades mounted on an annular shaft at the smaller end of the
duct of metal or cloth; (c) shutters fixed at the larger cross section end of the duct; (d)
windmill mounted on a rotatable stand to align the air inlet according to the direction of
the wind for optimal results.
2. A windmill generator substantially as herein described with reference to the
|Indian Patent Application Number||124/DEL/2002|
|PG Journal Number||45/2007|
|Date of Filing||18-Feb-2002|
|Name of Patentee||DHADWAL, SARITA SINGH|
|Applicant Address||W/O SARBJIT SINGH DHADWAL HOUSE NO. 876, GALI NO. 6, MOHALLA TIBBA SAHIB, HOSHIARPUR-146001, PUNJAB (INDIA)|
|PCT International Classification Number||F03D 9/00|
|PCT International Application Number||N/A|
|PCT International Filing date|