Solar Energy in India

 According to the prime minister, success in developing solar energy 'will change the face of India. It would also enable India to help change the destinies of people around the world. The plan intends to go beyond government to draw upon these assets'. India's plan to build 'solar cities' evolved from the prime minister's mission to build a 'green India'. 
  India, where most regions enjoy nearly 300 sunny days a year, is an ideal market for solar power companies. However, the high cost of light-to-electricity conversion -- at Rs 12 to Rs 20 per kWh (kilowatt-hour) -- has acted as a deterrent so far.
  Solar Energy
 The whole world is greatly concerned about tremendous increase in demand of energy and consequent depletion of convention energy sources like wood, coal oil etc. "At the present rate of energy consumption, the reserve of fossil fuels of the entire world can be exhausted in 50 to 100 years," said Dr. M. N. Nahar, principal scientist of the Division of Agriculture and Energy at the Central Arid Zone Research Institute (CAZRI). "There is an urgent need to harness solar energy and other alternative energy sources."
Unlike natural gas, coal, or nuclear power, solar power requires no fuel, works without polluting the air or leaving behind dangerous radioactive waste, and is extremely plentiful. Researchers estimate that the sun produces enough energy in a single second to meet the needs of all humanity for 2000 years. "The surface of the Earth receives an amount of solar energy equivalent to roughly 10,000 times the world energy demand," wrote Erik Lysen in the January 2003 issue of Renewable Energy World magazine. 
  India receives about 300 clear sunny days in a year. This is equal to over 5,000 trillion kWh/year, which is far more than the total energy consumption of the country in a year The daily average solar energy incident over India varies from 4-7 kWh/m2, depending upon location.

Solar Photo Voltaic systems
 Solar Photo Voltaic systems have found applications in households, agriculture, telecommunications, defense, and railways among others. In the last two decades, the cost of PV has gone down by more than 10 times, increasing accessibility for dispersed rural applications. Costs are expected to reduce further thus creating more potential About 62 MW aggregate capacity (about 10,50,000 individual PV systems and power plants) have been installed for various applications. In addition, PV products of 48 MW capacity have been exported. 
  Under MNES's PV programme, around 8.20 lakh systems have been installed - aggregating to about 29 MW. This includes 509,894 solar lanterns, 2,56,673 home lighting systems, 47,969 street lighting systems, and 5,000 water pumping systems. About 3.97 MWp of aggregate capacity of stand-alone and grid interactive PV power plants have been installed as on March 31, 2003. These include State's own programmes also MNES is implementing two major schemes for the deployment of stand-alone PV systems in the country:
Lighting systems, stand-alone power plants and other specialized systems, implemented mainly through SNAs/departments/corporations, Aditya  solar shops operated by Manufacturers Associations and NGOs.
Water-pumping systems for agriculture and related uses, implemented through IREDA and SNAs West Bengal, Rajasthan, hilly regions of Uttar Pradesh, Ladakh, Lakshadweep, Andaman and Nicobar Islands are prominent regions where SPV home lighting systems and power plants are in demand. About 3600 remote villages and hamlets have been electrified with SPV systems and power plants. Out of these 800 remote villages have been electrified during 2001-02 and 2002-03. Eleven power plants of 250 kWp aggregate capacity have been installed in Sagar Islands in West Bengal Aims and Targets. A wide range of power technologies exist which can make use of the solar energy reaching Earth. 
  Indian government planning to develop solar cities
  Indian government announced recently that it was planning to develop solar cities to reduce about 10 per cent usage of conventional energy sources through renewable energy installations and energy efficiency.
During the 11th Plan period, a total of 60 cities are proposed to be developed as solar cities, based on a model already practised in New York in the United States, Tokyo in Japan, and London in Britain.  India too targets a 10 to 20 per cent carbon emission reduction in the next 10 to 20 years.
  Under the government's solar city scheme, each of the 60 urban local governments would be provided a total of Rs 50 lakh (Rs 5 million) assistance of which Rs 10 lakh (Rs 1 million) would be for preparation of a master plan, Rs 10 lakh (Rs 1 million) for setting up a solar cell in the city council, Rs 10 lakh (Rs 1 million) for implementation of the plan over five years and the remaining Rs 20 lakh (Rs 2 million) for other promotional activities. A target of 50 MW has been set for solar power generation during the 11th Plan, which is likely to be achieved. India receives solar energy equivalent to over 5,000 trillion kilowatt hour per year.
 Solar energy systems, including street lights, garden lights, traffic lights, hoardings and solar water heaters will be installed in the city. Energy efficient 'green buildings' will be promoted on a large scale.
  Method of energy transformation
  A photovoltaic cell produces electricity directly from solar energy. Direct solar power involves only one transformation into a usable form. For example: Sunlight hits a photovoltaic cell (also called a photoelectric cell) creating electricity.
Hydroelectric power stations produce indirect solar power. The Itaipu Dam, Brazil /Paraguay Vegetation uses photosynthesis to convert solar energy to chemical energy, which can later be burned as fuel to generate electricity.  Methane (natural gas) and hydrogen may be derived from the biofuel. Hydroelectric dams and wind turbines are powered by solar energy through its interaction with the Earth's atmosphere and the resulting weather phenomena. Ocean thermal energy production uses the thermal gradients that are present across ocean depths to generate power. These temperature differences are ultimately due to the energy of the sun.
Solar  technologies: Most solar energy used today is harnessed as heat or electricity. Solar design is the use of architectural features to replace the use of grid electricity and fossil fuels with the use of solar energy and decrease the energy needed in a home or building with insulation and efficient lighting and appliances.
Insulating shutters for windows to be closed at night and on overcast days. These trap solar heat in the building. Fixed awnings positioned to create shade in the summer and exposure to the sun in the winter.
Movable awnings to be repositioned seasonally. A well insulated and sealed building envelope.  Active thermal solar panels using a heat transfer fluid (water or antifreeze solution). These are heated by the sun and the heat is carried away by circulation of the fluid for domestic hot water or building heating or other uses.
Solar heating systems: Solar heating systems are generally composed of solar thermal collectors, a fluid system to move the heat from the collector to its point of usage, and a reservoir to stock the heat for subsequent use. The systems may be used to heat domestic hot water or a swimming pool, or to provide heat
for a heating circuit . The heat can also be used for industrial applications or as an energy input for other uses such as cooling equipment.
Solar thermal cooling: There are some new applications of thermal hot water, such as air cooling, currently under development. The absorber machine works like a refrigerator. It uses hot water to compress a gas that, once expanded, will produce an endothermic reaction, which cools the air.
Concentrated Solar Power (CSP) Plants:  A concentrating solar power plant, Parabolic trough power plants are the most successful and cost-effective CSP system design at present.
Solar chimney: A solar chimney is a relatively low tech solar thermal power plant where air passes under a very large agricultural glass house (between 2 and 30 km in diameter), is heated by the sun and channeled upwards towards a convection tower. It then rises naturally and is used to drive turbines, which generate  electricity.
Energy Tower: An Energy tower is an alternative proposal for the solar chimney. The "Energy Tower" is driven by spraying water at the top of the tower; evaporation of water causes a downdraft by cooling the air thereby increasing its density, driving wind turbines at the bottom of the tower. It requires a hot arid climate and large quantities of water, but it does not require a large glass house.
Solar pond: A solar pond is a relatively low-tech, low cost approach to harvesting solar energy. The principle is to fill a pond with 3 layers of water.
Solar chemical: Solar chemical refers to a number of possible processes that harness solar energy by absorbing sunlight in a chemical reaction in a way similar to photosynthesis in plants but without using living organisms. No practical process has yet emerged.
Solar cooking: A solar box cooker traps the Sun's power in an insulated box; these have been successfully used for cooking, pasteurization and fruit canning. Solar cooking is helping many developing countries, both reducing the demands for local firewood and maintaining a cleaner environment for the cooks. The first known western solar oven is attributed to Horace de Saussure.
Solar lighting: The interior of a building can be lit during daylight hours using fibre optic light pipes connected to a parabolic collector mounted on the roof. The manufacturer claims this gives a more natural interior light and can be used to reduce the energy demands of electric lighting.

source :http://www.gits4u.com/renew & http://eai.in/blog/2009/07/cost-of-solar-power-in-india-over-rs-15.html

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Micro-hydro generator - DIY

Micro hydro power was once the world’s prominent source of mechanical power for manufacturing. Micro hydro is making a comeback for electricity generation in homes. Increasing numbers of small hydro systems are being installed in remote sites in North America. There’s also a growing market for micro hydro electricity in developing countries. This article is a technical over-view.

 

Micro hydro power is gradually assuming the decentralized form it once had. Water power predates the use of electricity. At one time hydro power was employed on many sites in Europe and North America. It was primarily used to grind grain where water had a vertical drop of more than a few feet and sufficient flow. Less common, but of no less importance, was the use of hydro to provide shaft power for textile plants, sawmills and other manufacturing operations.

Over time thousands of small mills were replaced by centrally-generated electric power. Many major hydroelectric projects were developed using large dams, generating several megaWatts of power. In many areas, hydro electric power is still used on a small scale and is arguably the most cost-effective form of energy.

Renewable energy sources such as wind and solar are being scaled up from residential to electric utility size. In contrast, hydro power is being scaled down to residential size. The small machines are similar in most ways to the large ones except for their scale.

Siting a hydro system is much more site-specific than a wind or photovoltaic (PV — solar electric) system. A sufficient quantity of falling water must be available. The vertical distance the water falls is called head and is usually measured in feet, meters, or units of pressure. The quantity of water is called flow and is measured in gallons per minute (gpm), cubic feet per second (cfs), or liters per second (l/s). More head is usually better because the system uses less water and the equipment can be smaller. The turbine also runs at a higher speed. At very high heads, pipe pressure ratings and pipe joint integrity become problematic. Since power is the product of head and flow, more flow is required at lower head to generate the same power level. More flow is better, even if not all of it is used, since more water can remain in the stream for environmental benefits.

A simple equation estimates output power for a system with 53% efficiency, which is representative of most micro hydro systems: 

Net Head* (feet) x Flow (US gpm) / 10 = Output (Watts)

* Net head is the pressure available after subtracting losses from pipe friction. Most hydro systems are limited in output capacity by stream conditions. That is, they cannot be expanded indefinitely like a wind or PV system. This means that the sizing procedure may be based on site conditions rather than power needs. The size and/or type of system components may vary greatly from site to site. System capacity may be dictated by specific circumstances (e.g. water dries up in the summer). If insufficient potential is available to generate the power necessary to operate the average load, you must use appliances that are more energy-efficient and/or add other forms of generation equipment to the system. Hybrid wind/PV/hydro systems are very successful and the energy sources complement each other.

The systems described here are called "run of river"; i.e. water not stored behind a dam. Only an impoundment of sufficient size to direct the water into the pipeline is required. Power is generated at a constant rate and if not used, it is stored in batteries or sent to a shunt load. Therefore, there is little environmental impact since minimal water is used. There is also much less regulatory complication.
System Types
If electric heating loads are excluded, 300-400 Watts of continuous output can power a typical North American house. This includes a refrigerator/freezer, washing machine, lights, entertainment and communication equipment, all of standard efficiency. With energy-efficient appliances and lights and careful use management, it is possible to reduce the average demand to about 200 Watts continuous.

Power can be supplied by a micro hydro system in two ways. In a battery-based system, power is generated at a level equal to the average demand and stored in batteries. Batteries can supply power as needed at levels much higher than that generated and during times of low demand the excess can be stored. If enough energy is available from the water, an AC-direct system can generate power as alternating current (AC). This system typically requires a much higher power level than the battery-based system.
Battery-Based Systems
Most home power systems are battery-based. They require far less water than AC systems and are usually less expensive. Because the energy is stored in batteries, the generator can be shut down for servicing without interrupting the power delivered to the loads. Since only the average load needs to be generated in this type of system, the pipeline, turbine, generator and other components can be much smaller than those in an AC system.
===============================Power = The rate of doing work
(IE Watts or horsepower)

1 Watt = 1 Volt X 1 Ampere

1 Horsepower = 746 Watts

1000 Watts consumed = 1 kiloWatt-Hour
(IE the unit found on utility bills)
===============================
Very reliable inverters are available to convert DC battery power into AC output (120 volt, 60 Hz). These are used to power most or all home appliances. This makes it possible to have a system that is nearly indistinguishable from a house using utility power.

The input voltage to the batteries in a battery-based system commonly ranges from 12 to 48 Volts DC. If the transmission distance is not great then 12 Volts is often high enough. A 24 Volt system is used if the power level or transmission distance is greater. If all of the loads are inverter-powered the battery voltage is independent of the inverter output voltage and voltages of 48 or 120 may be used to overcome long transmission distances. Although batteries and inverters can be specified for these voltages, it is common to convert the high voltage back down to 12 or 24 Volts (battery voltage) using transformers or solid state converters.

Wind or solar power sources can assist in power production because batteries are used. Also, DC loads (appliances or lights designed for DC) can be operated directly from the batteries. DC versions of many appliances are available, although they often cost more and are harder to find, and in some cases, quality and performance vary.
AC-Direct Systems
This is the system type used by utilities. It can also be used on a home power scale under the right conditions. In an AC system, there is no battery storage. This means that the generator must be capable of supplying the instantaneous demand, including the peak load. The most difficult load is the short-duration power surge drawn by an induction motor found in refrigerators, freezers, washing machines, some power tools and other appliances. Even though the running load of an induction motor may be only a few hundred Watts, the starting load may be 3 to 7 times this level or several kiloWatts. Since other appliances may also be operating at the same time, a minimum power level of 2 to 3 kiloWatts may be required for an AC system, depending on the nature of the loads.

In a typical AC system, an electronic controller keeps voltage and frequency within certain limits. The hydro’s output is monitored and any unused power is transferred to a "shunt" load, such as a hot water heater. The controller acts like an automatic dimmer switch that monitors the generator output frequency cycle by cycle and diverts power to the shunt load(s) in order to maintain a constant speed or load balance on the generator. There is almost always enough excess power from this type of system to heat domestic hot water and provide some, if not all, of a home’s space heating.
System Components
An intake collects the water and a pipeline delivers it to the turbine. The turbine converts the water’s energy into mechanical shaft power. The turbine drives the generator which converts shaft power into electricity. In an AC system, this power goes directly to the loads. In a battery-based system, the power is stored in batteries, which feed the loads as needed. Controllers may be required to regulate the system.
Pipeline
Most hydro systems require a pipeline to feed water to the turbine. The exception is a propeller machine with an open intake. The water should pass first through a simple filter to block debris that may clog or damage the machine. The intake should be placed off to the side of the main water flow to protect it from the direct force of the water and debris during high flows.It is important to use a pipeline of sufficiently large diameter to minimize friction losses from the moving water. When possible, the pipeline should be buried. This stabilizes the pipe and prevents critters from chewing it. Pipelines are usually made from PVC or polyethylene although metal or concrete pipes can also be used.

                       

mpulse Runner       Francis Runner     Turgo Runner

Turbines
Although traditional waterwheels of various types have been used for centuries, they aren’t usually suitable for generating electricity. They are heavy, large and turn at low speeds. They require complex gearing to reach speeds to run an electric generator. They also have icing problems in cold climates. Water turbines rotate at higher speeds, are lighter and more compact. Turbines are more appropriate for electricity generation and are usually more efficient.

There are two basic kinds of turbines: impulse and reaction.

Impulse machines use a nozzle at the end of the pipeline that converts the water under pressure into a fast-moving jet. This jet is then directed at the turbine wheel (also called the runner), which is designed to convert as much of the jet’s kinetic energy as possible into shaft Common impulse turbines are pelton, turgo and cross-flow.

In reaction turbines the energy of the water is converted from pressure to velocity within the guide vanes and the turbine wheel itself. Some lawn sprinklers are reaction turbines. They spin themselves around as a reaction to the action of the water squirting from the nozzles in the arms of the rotor. Examples of reaction turbines are propeller and Francis turbines.
Turbine Applications
In the family of impulse machines, the pelton is used for the lowest flows and highest heads. The cross-flow is used where flows are highest and heads are lowest. The turgo is used for intermediate conditions. Propeller (reaction) turbines can operate on as little as two feet of head. A turgo requires at least four feet and a pelton needs at least ten feet. These are only rough guidelines with overlap in applications.

The cross-flow (impulse) turbine is the only machine that readily lends itself to user construction. They can be made in modular widths and variable nozzles can be used.

Most developed sites now use impulse turbines. These turbines are very simple and relatively cheap. As the stream flow varies, water flow to the turbine can be easily controlled by changing nozzle sizes or by using adjustable nozzles. In contrast, most small reaction turbines cannot be adjusted to accommodate variable water flow. Those that are adjustable are very expensive because of the movable guide vanes and blades they require. If sufficient water is not available for full operation of a reaction machine, performance suffers greatly.

An advantage of reaction machines is that they can use the full head available at a site. An impulse turbine must be mounted above the tailwater level and the effective head is measured down to the nozzle level. For the reaction turbine, the full available head is measured between the two water levels while the turbine can be mounted well above the level of the exiting water. This is possible because the "draft-tube" used with the machine recovers some of the pressure head after the water exits the turbine. This cone-shaped tube converts the velocity of the flowing water into pressure as it is decelerated by the draft tube’s increasing cross section. This creates suction on the underside of the runner.

Crossflow Turbine

            Propeller Turbine

   

 

Centrifugal pumps are sometimes used as practical substitutes for reaction turbines with good results. They can have high efficiency and are readily available (both new and used) at prices much lower than actual reaction turbines. However, it may be difficult to select the correct pump because data on its performance as a turbine are usually not available or are not straightforward.

One reason more reaction turbines are not in use is the lack of available machines in small sizes. There are many potential sites with 2 to 10 feet of head and high flow that are not served by the market.
Generators
Most battery-based systems use an automotive alternator. If selected carefully, and rewound when appropriate, the alternator can achieve very good performance. A rheostat can be installed in the field circuit to maximize the output. Rewound alternators can be used even in the 100–200 Volt range.

For higher voltages (100–400 Volts), an induction motor with the appropriate capacitance for excitation can be used as a generator. This will operate in a small battery charging system as well as in larger AC direct systems of several kiloWatts.

Another type of generator used with micro hydro systems is the DC motor. Usually permanent magnet types are preferable. However, these have serious maintenance problems because the entire output passes through their carbon commutators and brushes.

Batteries Lead-acid deep-cycle batteries are usually used in hydro systems. Deep-cycle batteries are designed to withstand repeated charge and discharge cycles typical in RE systems. In contrast, automotive (starting) batteries can tolerate only a fraction of these discharge cycles. A micro hydro system requires only one to two days storage. In contrast, PV or wind systems may require many days’ storage capacity because the sun or wind may be unavailable for extended periods. Because the batteries in a hydro system rarely remain in a discharged state, they have a much longer life than those in other RE systems. Ideally, lead-acid batteries should not be discharged more than about half of their capacity. Alkaline batteries, such as nickel-iron and nickel-cadmium, can withstand complete discharge with no ill effects.
Controllers
Hydro systems with lead-acid batteries require protection from overcharge and over-discharge. Overcharge controllers redirect the power to an auxiliary or shunt load when the battery voltage reaches a certain level. This protects the generator from overspeed and overvoltage conditions. Overdischarge control involves disconnecting the load from the batteries when voltage falls below a certain level. Many inverters have this low-voltage shutoff capability.

An ammeter in the hydro output circuit measures the current. A voltmeter reading battery voltage roughly indicates the state of charge. More sophisticated instruments are available, including amp-hour meters, which indicate charge level more accurately.
Conclusions
Despite the careful design needed to produce the best performance, a micro hydro system isn’t complicated. The system is not difficult to operate and maintain. Its lifespan is measured in decades. Micro hydro power is almost always more cost-effective than any other form of renewable power.

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Multi stage wind turbine - DIY

CONSTRUCTION DETAILS OF EACH STAGE

It includes construction of one conical lift device three leaf blade horizontal axis wind rotors. These are explained below,

Construction of conical lift device:

At first sheet metal strips are fastened over the surface of hollow cone element using rivet. Then the hub which holds the device at the beginning of the shaft is inserted into the inner side of the device. The metal plates are used to connect the hub with conical lift device.

Table: Specification of conical lift device

Length
Larger diameter	155
Smaller diameter	15
Metal blade thickness	0.2
Tapper of blades	(1-3”)
No of blades	10

Construction of wind blades from PVC pipes and hub:

At first take PVC with particular length depending upon the diameter of the pipe. The length of pipe will be 5 times of its diameter (for example 8” pipe length must be 40”). The conical lift device hub is coupled with the shaft through the hub’s bush. The beginning 30cm of the 2.1m shaft are occupied by the conical device.

Fig PVC pipe cuttings

Divide the pipe into 6 equal parts by the angle 60 deg longitudinally. Then cut these rectangle shaped pieces into tapered blade shape.

Fig : Angle of cutting

Remove the excess materials from the blades by cutting the materials from the PVC to form a perfect blade. The edges of the blades are machined to form a shape of aerofoil.

Fig : Hub

Then make two holes to fastening the blades with respective hubs.

Fig : Final shape of blade

Construction details of leaf blade rotors.

First stage:

The specifications of the last three stages are explained below in table. The blades are first fastened with extension plate for the purpose of increasing the rotor diameter and also make the blades to receive the fresh wind.

Fig : Fixing of blades with hub

Fig : First stage rotor

Table : First stage specifications

No of blades	6
Length of extending plate	0.03m
Length of blade	0.67m
Diameter of hub	0.16m
Distance from beginning stage	0.20m

Second stage:

The second stage preparation is same as that of the first stage. The only differences between these two stages are by its length of blade. The second stage rotor blades are from 6” pipe.
Fig : Second stage rotor


Table : Second stage specification

No of blades	6
Length of extending plate	0.035m
Length of blade	0.100m
Diameter of hub	0.20m
Distance from beginning stage	0.75m

Third stage:

The third stage contains 12 blades each blade is made from 8” PVC pipe. The construction of the third stage is same as that of the last two stages

Fig: Third stage rotor

Table 7.3.3: Third stage specification

No of blades	12
Length of extending plate	0.04m
Length of blade	0.150m
Diameter of hub	0.20m
Distance from beginning stage	0.85m

WORKING PRINCIPLE FOR WIND TURBINES:

When an airfoil-shaped body moved through a fluid produces an aerodynamic force due to the Bernoulli’s principle (the pressure of air at lower end is higher than top surface). The component of this force perpendicular to the direction of motion is called lift. This lift force is only responsible for rotation of the wind turbine.

Fig : Working principle of wind turbine

In PVC wind blades the cross are made as aerofoil to convert the velocity of wind into mechanical rotary motion.

PRINCIPLE BEHIND MULTISTAGE WIND TURBINE:

The principle for the multistage wind turbine is the modification from the principle of multi rotor wind turbine. Our new multistage principle increases the no of rotors in a single rotating shaft for the purpose of increasing the speed of the rotor and also the power. The principle for multistage wind turbine is explained below.

Principle for multi-rotor wind turbine:

By the principle of Bertz there is nothing possibility to built a multi rotor wind turbines at      series in horizontal position. It’s only material waste.

But at the same time from the principle of Doug Selsam by increase the angle of shaft ( horizontal to +ve angles)  (or) inclined the angle position there is some chances to built a multi rotor wind turbines by giving  wind to all rotors. From this we will construct a multi stage wind turbine.

Fig : Working principle of multistage wind turbine

Principle for multi-rotor wind turbine:

From the Selsam’s multi-rotor wind turbine principle, in our multi stage wind turbine we just use various diameter rotors in a single rotating shaft by increasing the distance between the rotors and we use a new type of double plate tail for conical lift device to receive air flow first.

We also inclined the rotating shaft for the purpose of receiving the fresh air for each stage. The diagram below shows the principle for multi-rotor wind turbine.

Fig : Principle for multistage wind turbine

WORKING OF CONICAL LIFT DEVICE:

When the air flows in-between the two blades horizontally then there is a pressure difference is produced due to the shape of the blades. By the application of Bernoulli's theorem the total device is moved to the low pressure side (clock wise from front). At the bigger side of the cone the air was completely blocked by the bending blades. This makes more pressure differences to turn device at slow wind speeds.  

Fig : Working of conical lift device

The conical lift device works as an initiator in the multi stage wind turbine. The cut in speed for the conical lift device will be 3.8m/s. that help to speed up the turbine at low wind speed.

CONSTRUCTION DETAILS

The construction of the multistage wind turbine consists of three major parts, these are explained below.

• Supporting unit.
• Rotor and tail unit.
• Transmission unit.

SUPPORTING UNIT:

The supporting unit consists of supporting c –channels with inclined positions by the principle of multistage wind turbine. The supporting columns are not equal and also they are not perpendicular with the bottom horizontal channel. The value of angle for the rotating shaft is given as 10 deg; by this we designed the angular positions of the supporting columns. The dimensions and positions of the supporting columns are explained in diagram below.

The total supporting column sets are fitted over the thrust bearing which is in the top of the supporting tower. The total top weight of the upper supporting setup was loaded over the thrust bearing using the iron rod.

Fig : Supporting unit


ROTOR AND TAIL UNIT:

Each rotor are situated in the 2meter length shaft with some space interval them, with respect to the diameter of the rotor. For larger diameter rotor requires more space interval from the beginning rotor. By the new principle of multistage wind turbine these rotors are situated with different space intervals.

Fig 12.2 (a): Rotor and tail in turbine

The twin tail helps to turn the turbine to face the wind and also for conical lift device to receive the air first for the purpose increase the output power of the turbine.

Fig : View of tail from top


POWER TRANSMISSION UNIT:

Belt type power transmission is the cheapest power production system, with optimum efficiency. There is one larger pulley is fixed at the end of the shaft to transfer the power to smaller pulley which is fixed at the rotor’s alternator. The specifications of the belt drive transmission system are given below.

Type of the belt                                = v- belt
Larger pulley diameter                     = 254mm
Smaller pulley diameter                    = 5.08mm
Length of belt                                    = 3200.4mm
Material of the pulley                        = cast iron


Fig : Power transmission unit

WORKING OF MULTI STGE WIND TURBINE

When the air first hits the conical lift device then turbine starts rotating. That lift device helps to rotate the turbine. After the sufficient torque for the turbine are offered by another three stages in the unit. Fresh air is entered into the each stage for achieving maximum torque.

Then that torque was transmitted to the alternator by using belt drive transmission system. Considering the distance between the rotor shaft and the alternator we use belt drive for power transmission.

The alternator that helps to transfers the mechanical torque into electrical power. The tail that helps to turn the turbine to face the maximum wind power by receive wind conical lift device first.

POWER OUTPUT

S.NO	STAGES	RPM	WIND SPEED              (m/s)	OUTPUT POWER  (w)
1	Conical lift device only	105	4.5	4.3
2	Conical lift device and first stage rotor	85	4.5	7.5
3	Conical lift device, first stage rotor and second stage rotor	52	4.5	12.6
4	Conical lift device, first stage rotor, second stage rotor and third stage rotor	39	4.5	16

At 12.5 m/s the output power will be more than 300 watts. We expect 50 watts at 4.5m/s but due to belt drive transmission and poor alternator reduces the power.

ADVANTAGES

• Alternate power generating unit.

• Cost effective then compared to other single stage turbines.

• Easy installation.

• Medium power production is possible up to 10KW.

• Maintenance cost is low.

• Cut in speed is 3.8m/s, at lower wind speed maximum power is possible.

• Non- polluting.

• Space occupied by the multistage wind turbine is lower compared to single stage wind turbines.

DISADVANTAGES

• Technical person is required for construction.

• Higher fixing cares to be taken avoid accident due to heavy wind flow.

• Additional power pack unit required for storing power in day time and use the power in night times.

• Proper rectifier is required for charging the battery.

Increase the power of the turbine by using super alternator and use light weight material like carbon fiber. By using the light weight materials to blades and also rotating shaft we can add more rotors to increase the power. Add furling units and better gear drive transmission system for better efficiency. Give better design for rotating the turbine to face the wind depending upon the flow direction. 

- Work done by arjun [selvaarjunanpts@gmail.com]

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