hybrid energy project

8/13/2019 hybrid energy project

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CHAPTER -I

INTRODUCTION

The main objective of this project is to develop a standalone power station in remote

areas where there is no power supply or load shedding is very high. It is not only restricted to

remote areas, as it is creating ecofriendly environment can be used in all the areas.

Hybrid power station is a combination ofphotovoltaic and wind turbines which is used

to generate electricity whenever there is availability of the natural energy source (wind and

solar) and store it to a battery bank via control panel, and use the electricity as per

requirement. It mainly consists solar power generation, wind power generation, conditional

based pumping system and inverter for AC appliances.

Fig 1.0 Block diagram of hybrid pumping system


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1.1 Solar powerSolar energy has the greatest potential of all the sources of renewable energy. The

solar cell receives the solar energy. The solar cells operate on the principle of photovoltaic

effect, by using solar cells. Basically the cells are placed in an open and fixed manner.

Photovoltaic cell is an alternate device used for power generation which converts suns

radiation directly into electrical power. Thus power generated can be stored and utilized.

Solar technologies are broadly characterized as either passive solar or active solar

depending on the way they capture, convert and distribute solar energy. Active solar

techniques include the use of photovoltaic panels and solar thermal collectors to harness theenergy. Passive solar techniques include orienting a building to the Sun, selecting materials

with favorable thermal mass or light dispersing properties, and designing spaces that

naturally circulate air.

1.2 Wind powerWith the recent surge in fossil fuels prices, demands for cleaner energy sources, and

government funding incentives, wind turbines have become a viable technology for power

generation. Currently, horizontal axis wind turbines (HAWT) dominate the wind energy

market due to their large size and high power generation characteristics. However, vertical

axis wind turbines (VAWT) are capable of producing a lot of power, and offer many

advantages. The mechanical power generation equipment can be located at ground level,

which makes for easy maintenance.

Wind turbines work by converting the kinetic energy in the wind first into rotational

kinetic energy in the turbine and then electrical energy that can be supplied. The energy

available for conversion mainly depends on the wind speed and the swept area of the turbine.

When planning a wind farm it is important to know the expected power and energy output of

each wind turbine to be able to calculate its economic viability.


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1.3 Conditional based pumping systemAutomated pumping system is used to regulate the flow control of water from the sump

to the tank, based on water level in the sump. To achieve this particular step we use micro

controllers, sensors and electronic switches to determine the water levels in sump and the

tank and fill the tank accordingly. The switches are used to start and stop pump automatically

whenever the water content inside the tank falls to a predetermined minimum and maximum

level. Its not only restricted to automated control but a manual circuitry is provided in the

case of emergency.


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CHAPTER -II

LITERARURE SURVEY

2.1 Different types of Solar Panels

There are different types of solar panels are available depending upon the operating

power, efficiency and cost. We have to select photovoltaic according to the application and

the efficiency of photovoltaic.

2.1.1 Monocrystalline modules

Monocrystalline, as the name suggests, is constructed using one single crystal, cut

from ingots. This gives the solar panel a uniform appearance across the entire module. These

large single crystals are exceedingly rare, and the process of 'recrystallizing' the cell is more

expensive to produce.

This technology is now the most widely available in Australia, with the cost of

producing Monocrystalline cells coming down every year. They are still more expensive than

polycrystalline, but can be up to 2% more efficient. EnviroGroup uses SunOwe (14.5%) and

Suntech (16.5%) monocrystalline solar modules for our installations.

Suntech have recently made some exciting developments in monocrystalline

efficiency, with the patent pending Pluto technology. Unique texturing technology, with

lower reflectivity, ensures more sunlight can be absorbed throughout the day even without

direct solar radiation, and thinner metal lines on the top surface reduces shading loss.

Importantly, the process was developed at the University of New South Wales, and has

achieved lab efficiency of 25%, and verified efficiency of approx 19%. These panels will be

more expensive, but will offer far more solar electricity for less area of solar panel.


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2.1.2 Polycrystalline modules

Polycrystalline (or multicrystalline) modules are composed of a number of different

crystals, fused together to make a single cell (hence the term 'multi'). They have long been the

most popular type of solar module, due to the lower cost in manufacturing the cells. Recently,

the cost of monocrystalline has come down, making them more popular in the residential

market.

As you can see in the image (left), the construction of these different crystals gives the

solar panel a visible crystal grain, or a 'metal flake effect'. They are slightly cheaper to

produce than Mono panels, but are also less efficient (anywhere from 0.5% to 2% less

efficient depending on the manufacturer). This is because the crystal grain boundaries cantrap electrons, which results in lower efficiency.

The BP Solar modules that EnviroGroup installs are approximately 13.5% efficient

(meaning that if 100 Watts of potential solar energy strikes the panel, it will produce

approximately 13.5 Watts of solar electricity).

These panels are very popular in Australia, and offer a good balance of value vs

performance.

2.1.3BI photovoltaic(building integrated photo voltaic)

Amorphous (or 'thin film') solar modules have recently become very popular in the

Australian market. They offer better performance in higher temperatures, and have some

benefits in shady locations. However, the benefits have been greatly exaggerated by some

suppliers, and it is important to weigh that up against the negatives of thin film technology.

The manufacture of these panels is highly automated - silicon is sprayed onto the substrate as

a gas (called 'vapour deposition'), which means that the silicon wafer is approx 1 micron thick

(compared to approx. 200 microns for mono and poly). This means that the panel uses less

energy to produce therefore will pay itself back from an energy point of view in a shorter

time. However, it also means that the panels are far less efficient than mono or poly (approx

5-6% efficient).

The electrical connections are etched by a laser. Etching these as long horizontal cells

across the panel makes these less susceptible from being blocked by shade, but it's important


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to recognise that there will still be a significant drop-off in performance when the panel is

shaded.

Thin-film panels are significantly less efficient than crystalline panels, and a greater

number is required for the same output. On average, a thin film solar array will need 2.5

times more roof area than mono or poly. This is critical if you intend to increase the size of

your system later, as you may take up all of your north-facing roof for a relatively small

system.

One of the biggest selling points of thin film is the performance in hotter

temperatures. Unfortunately this has been misrepresented by some suppliers of thin film

panels. As an example, if you live in Melbourne, and you are shown a graph that indicates the

performance of thin film panels in Alice Springs, it's obvious that those panels won't provide

the same advantage in a cooler climate.

2.2 Horizontal axis wind turbine vs. Vertical axis wind turbine

comparison.

Types

Performance

Horizontal axis Vertical axis

Power generation efficiency 50-60% Above 70%

Electromagnetic interface Yes No

Steering mechanism of wind Yes No

Gear box Above 10 KV No

Wind resistance capacity Week Strong

Noise 5-60 DB 0-10 DB

Starting wind speed High Low

Failure rate High Low

Rotating speed High Low

Cable starting problem Yes No

Power curve Depressed Full

Table 2.2Horizontal axis wind turbine vs. Vertical axis wind turbine comparison


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Permanent magnet alternators are can be very efficient, in the range of 60%-95%,

typically around 70% though. As a generator they do not require a controller as a typical

three phase motor would need. It is easy to rectify the power from them and charge a battery

bank or use with a grid tie.

It is easy to build a permanent magnet alternator, even for beginners. This is a

common choice for home builders. I will have some great information on this site a little later

that will take you through the design and building process. You just need to understand a

little science and have some sort of mechanical competency.

Note: Car alternators are not PMA but actually have a field coil instead of permanent

magnets, and are typically very inefficient around 50%. They typically need to be spun

1500+RPM to get any real power out of them, but with a belt or gear arrangement can still do

a decent job.

2.3.3 Brushed DC Motor

Brushed DC Motors are commonly used for home built wind turbines. They are

backwards from a permanent magnet generator. On a brushed motor, the electromagnets spin

on the rotor with the power coming out of what is known as a commutator. This does cause arectifying effecting outputting lumpy DC, but this is not an efficient way to rectify the

power from the windings, it is used because its the only way to get the power out of the

rotor. A good brushed motor can reach a good efficiency, but are typically at most 70%.

There are many great advantages to using a brushed motor. One of the biggest reasons

is because typically you can find one not requiring any gearing and still get a battery charging

voltage in light wind. They are also quite easy to find, they can be purchased from eBay,

surplus supply stores, industrial supply stores, and can find them on different things that

might get thrown away or given away (like a treadmill).


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2.3.4 Resources

A quantitative measure of the wind energy available at any location is called the Wind

Power Density (WPD) It is a calculation of the mean annual power available per square meter

of swept area of a turbine, and is tabulated for different heights above ground. Calculation of

wind power density includes the effect of wind velocity and air density. Color-coded maps

are prepared for a particular area described, for example, as "Mean Annual Power Density at

50 Metres". In the United States, the results of the above calculation are included in an index

developed by the National Renewable Energy Laboratory and referred to as "NREL CLASS".

The larger the WPD calculation, the higher it is rated by class. Classes range from Class 1

(200 watts per square metre or less at 50 m altitude) to Class 7 (800 to 2000 watts per square

m). Commercial wind farms generally are sited in Class 3 or higher areas, although isolated

points in an otherwise Class 1 area may be practical to exploit.

Wind turbines are classified by the wind speed they are designed for, from class I to

class IV, with A or B referring to the turbulence.

Class Avg. Wind Speed (m/s) Turbulence

IA 10 18%

IB 10 16%

IIA 8.5 18%

IIB 8.5 16%

IIIA 7.5 18%

IIIB 7.5 16%

IVA 6 18%

IVB 6 16%

Table 2.3 Classes of wind turbines


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2.4 Different Types of Water Pumps

Water pumps are appliances that move water from the source or storage area to the

point where it will be used by consumers. A water pump represents a sizable investment and

may require maintenance and repair costs over its lifetime.

2.4.1 Jet Pumps

A jet pump can be installed at a couple of different depths below the ground. The

shallow and deep well jet pumps will pull water out of the ground between 25 feet and 100

feet. Bothtypes of jet pumps use a vacuum effect to pull water out of the well and pump it to

the well equipment outside the home.

2.4.2 Submersible Well Pumps

Submersible water pumps perform the opposite job to retrieve water from the well,

pushing water up from the well instead of using the machinery to pull the water out of the

hole. These types of pumps are lowered deeper into the ground, according to the

specifications of the local water district for obtaining ground water.

2.4.3 Sewer Sump pumpspumps are needed to pump sewage water from the house into the septic system. Inside

the septic tank, the water will break down and return to the soil through the soil absorption

system. The sewer sump pump is a pump submersed into the ground. Pumping the septic tank

every few years will help to improve the life of the sump pump.

2.4.4 Circulation Pumps

Water circulation pumps are needed to circulate water around the house. Two

examples are pumps that pump water from the water purifier tanks outside into the house and

the water pumps that send water from the hot water heater into the bathroom, kitchen and

laundry room. The water circulation pump may use centrifugal force to pump water from the

source to the destination.


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2.5 Battery types

Depending upon the life cycles and efficiency can be used with photovoltaic.

2.5.1 The Lead Acid Battery

This is the type of battery you are most likely to be using in a static situation. It is the most

cost effective and is capable of producing high currents.

These have been around for a long time, having been invented in the mid 1800's with the

basic design principally unchanged.

The battery consists of individual cells, each producing approximately 2 volts. Each cell

consists essentially of two electrodes of lead, in a 33% solution of sulphuric acid. As the

battery is charged however, chemical changes occur in both the electrodes and the

electrolyte (the sulphuric acid).

The lead acid battery described above is known as a wet cell lead acid battery due to the

electrolyte being liquid.

2.5.2 Deep Cycle Batteries

The type of battery fitted to a car or truck is designed to give a high current for starting the

vehicle but this would normally only discharge the battery by a maximum of 10%.

For a solar powered home, however, batteries designed for Deep Cycle use are required.

These batteries, while not being able to supply the high current of a Starting Battery, will

cope with regular discharging by 40% and occasional discharging by 80%.

Batteries described as Leisure Batteries are a halfway house between a Starting Battery and

a Deep Cycle Battery, and may be suitable for a week-end home where the batteries are

normally maintained in a fully charged state.


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2.5.3 OGi Batteries

These are standard flat plate vented batteries as described above, otherwise described as a

VLA or Flooded Lead Acid batteries.

2.5.4 OGiV Batteries

These are again of flat plate design but are semi-sealed or VRLA (Valve Regulated Lead

Acid). Valve Regulated batteries have the following advantages which may or maynot be

important when used in a solar power setup:

Release of hydrogen during charging is significantly reduced, reducing (though noteliminating) the need for ventilation.

No topping up of the cells with distilled or demineralised water is required There is no chance of acid spillage Batteries can be designed to be place horizontally or to be stacked, reducing floor

space requirement.

There can however be disadvantages with the VRLA design, including:

No ability to top up the battery if the electrolite should be low May not cope with higher temperatures as drying out may occur.

2.5.5 OPzS

These batteries are a type VLA vented battery using tubular positive plates.

2.5.6 OPzV

OPzV batteries are a type of VRLA with tubular positive plates .

Two other types are also available, both of which may be termed a sealed lead acid battery

though they do have a pressure relief valve:

Absorbed Glass Mat (AGM) - where the electrolyte is absorbed in a fine fibreglassmat between the electrodes

Gel - where the electrolyte is in the form of a gel.


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Both the above types of battery can withstand being turned over without spilling electrolyte

and therefore have specific uses.

Due to these batteries being at least semi sealed, care has to be taken to ensure that no

excessive gassing occurs (which occurs at higher charging voltages). Therefore these

batteries may require a specific charge controller. Charging with the wrong type of

controller can cause an explosion.


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CHAPTERIII

HYBRID POWER GENERATION

3.1Solar power generation

The solar energy can be directly converted into electrical energy by means of

photovoltaic effect, i.e. conversion of light into electricity. Generation of an electromotive

force due to absorption of ionizing radiation is known as photovoltaic effect.

The energy conversion devices which are used to convert sunlight to electricity by use of

the photovoltaic effect are called solar cells. Photo voltaic energy conversion is one of the

most popular nonconventional energy sources. The photovoltaic cell offers an existing

potential for capturing solar energy in a way that will provide clean, versatile, renewable

energy. This simple device has no moving parts, negligible maintenance costs, produces no

pollution and has a lifetime equal to that of a conventional fossil fuel. Photovoltaic cells

capture solar energy and convert it directly to electrical current by separating electrons from

their parent atoms and accelerating them across a one way electrostatic barrier formed by

the function between two different types of semiconductor material.

3.1.1 Photo Voltaic Effect on Semiconductors

Semiconductors are materials which are neither conductors nor insulators. The photo

voltaic effect can be observed in nature in a variety of materials but semiconductors has

shown best performance.

When photons from the sun are absorbed in a semiconductor they create for electrons

with higher energies than the electrons which provide the boarding in the base crystal.Once

these electrons are created, there must be an electric field to induce these higher energy

electrons to flow out of the semiconductor to do useful work. The electric field in most solar

cells is provided by a junction of materials which have different electrical properties.

To understand more about the functioning and properties of semiconductors, let us

briefly discuss. Semiconductors are classified into

1) Extrinsic semiconductor

2) Intrinsic semiconductor.


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3.1.2 PN-Junction Silicon Solar Cell

A PN junction is formed from a piece of semiconductor by diffusing P-type

materials to one half side and N-type materials to other half side.

It consists of both types of semiconductor materials. The N-type layer is situatedtowards the sunlight. As N-type layer is thin, light can penetrate through it.

The energy of the sunlight will create free electron in the N-type material and holes in

the p type material. This condition built up the voltage with in the crystal. Because the holes

will travel to the +ve region and the holes will travel to the -ve region. This conduction

ability is one of the main technical goals in fabricating solar cells.

3.1.3 Purification and Reformation into WafersThe purification process basically entails high temperature melting of the sand and

simultaneous reduction in the presence of hydrogen. This results in a very pure

polycrystalline form of silicon.

The next step is to reform this silicon into a single crystal and then cut the crystal into a

single crystal and then cut the crystal into individual wafers. There are two methods namely

czochralskigrowth method and film fed growth. The former method produces single,

cylindrical crystals and later produces continuous ribbon of silicon crystals.

Then this cylindrical crystal and ribbon crystal is transformed into disc shaped cells

and rectangular cells by slicing. After that one side is doped by exposure to high temperature

phosphorus, forming a thin layer of N type material. Similarly p type is made. Electrical

contacts are applied to the two surfaces, an anti-reflection coating is added to the entire

surface and the entire cell is then sealed with protective skin.

3.1.4 Antireflective Coating

Antireflective coating (ARC) is an important part of a solar cell since the bare silicon

has a reflection coefficient of 0.33 to 0.54 in the spectral range of 0.35 to 1.1 cm. The arc not

only reduces the reflection losses but also lowers the surface recombination velocity. A single

optimal layer of ARC can reduce the reflection to 10 percent and two layers can reduce the

reflection up to 3 percent in desired range of wavelengths.

Generally Arcs are produced on the solar cell by vacuum evaporation process and the

coatings which are tried are SiO2, SiO, Al2O3, TiO2, Ta2O5and Si3N4. Other methods of

deposition are sputtering, spin-on, spray-on or screen printing. Only the vacuum evaporation


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sputtering give good results but are expensive. The average reflection can be further reduced

by using two antireflective coatings instead of one where the outside (exposed side) coating

has an index of refraction 1.3 to 1.6 and the second layer between silicon and the first layer

has an index of refraction 2.2 to 2.6. This two layer ARC gives a better impedance match

between the index of silicon and the index of air.

Fig 3.1 reflective coating

Fig 3.2 A typical n-on-p-Photovoltaic


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Fig 3.3 Typical current-voltage characteristics of a solar cell

3.2wind power generation

Wind turbines operate on a simple principle. The energy in the wind turns two or three

propeller-like blades around a rotor. The rotor is connected to the main shaft, which spins a

generator to create electricity.

Wind turbines are mounted on a tower to capture the most energy. At 100 feet (30 meters) or

more above ground, they can take advantage of faster and less turbulent wind.

Wind turbines can be used to produce electricity for a single home or building, or they can be

connected to an electricity grid (shown here) for more widespread electricity distribution.

3.2.1GeneratorThe Permanent Magnet Generator (PMG) - that produces at least 1 volt DC for every 25

RPM, thus wind turbine blades turn at 400 RPM would generate 16 VDC. A 260 VDC, 5 A

continuous duty treadmill motor with a 6 inch threaded hub is well suited for a small wind

turbine.You can get about 7 amps in a 30 mph wind. In other words, it is a simple, cheap little

machine to get you started.


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A 90 VDC, 20A Treadmill motor requires an upgrade to most of the original instructions due

to the increase in size and weight. It also produces a lower output voltage. The motor is better

suited for a system with gearing to increase the RPM.

3.2.2 How much power can we get from the wind.

Power available in the wind = .5 x air density x swept area x (wind velocity cubed)

Example: air density = 1.23 kg per cubic meter at sea level. Swept area = pi x r squared. Our

2 foot blades = 0.609m, 4 ft = 1.219m. 10 mph = 4.4704 m/s, 20 mph = 8.9408 m/s.

How much power is in the wind: 2 ft blade, 10 mph winds = .5 x 1.23 x 3.14 x 0.609squared

x 4.4704 cubed

= .5 x 1.23 x 1.159 x 89.338 = 63.7 watts

With 4 foot blades and 10 mph winds = .5 x 1.23 x 4.666 x 89.338 = 256 watts

With 4 foot blades and 20 mph winds = .5 x 1.23 x 4.666 x 714.708 = 2051 watts

That's the MAXIMUM power in the wind. However, it's impossible to harvest ALL the

power. The Betz Limittells us that the maximum percentage of power we can harvest from

the wind is 59.26%.

Thus our maximum power from these turbines would be:

2 ft blades, 10 mph wind = 37.7 watts

4 ft blades, 10 mph wind = 152 watts

4 ft blades, 20 mph wind = 1,215 watts

These values are the maximum power achievable. The results will be less, depending on how

well shape the blades, how well balanced the blade assembly.


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CHAPTER IV

CIRCUIT DIAGRAM AND DESCRIPTION

4.1 conditional based water pumping.

A water level controller based using 8051 is shown in this article. A lot of water level controller

projects have been published in this website but is the first one based on a microcontroller. This

water level controller monitors the level of the overhead tank and automatically switches on the

water pump whenever the level goes below a pre-set limit. The level of the overhead tank is

indicated using 4 leds and the pump is switched of when the overhead tank satisfies the

condition the pump stops. The pump is not allowed to start if the water level in the sump tank is

low and also the pump is switched off when the level inside the sump tank goes low during a

pumping cycle. The circuit diagram of the water level controller is shown above.

The level sensor probes for the overhead tank are interfaced to the port 2 of the microcontroller

through transistors. Have a look at the sensor probe arrangement for the overhead tank in Fig. A

positive voltage supply probe goes to the down bottom of the tank. The probes for sensing 1/4,

1/2, 3/4 and FULL levels are placed with equal spacing one by one above the bottom positive

probe. Consider the topmost (full level) probe, its other end is connected to the base of transistor

Q4 through resistor R16. Whenever water rises to the full level current flows into the base of

transistor Q4 which makes it ON and so its collector voltage goes low. The collector of Q4 is

connected to P2.4 and a low voltage at P2.4 means the overhead tank is not FULL. When water

level goes below the full level probe, the base of Q2 becomes open making it OFF. Now its

collector voltage goes high and high at P2.4 means the tank is not full. The same applies to other

sensor probes (3/4, 1/2, 1/4) and the microprocessor understands the current level by scanning the

port pins P2.4, P2.5, P2.6 and P2.7. Allthese port pin are high (all sensor probes are open) means

the tank is empty.

Port pin P0.5 is used to control the pump. Whenever it is required start pumping, the controller

makes P0.5 low which makes transistor Q6 ON which in turn activates the relay K1 that switches

the pump. Also the LED d6 glows indicating the motor is ON. LED D7 is the low sump indicator.

When the water level in the sump tank goes low, the controller makes P0.7 low which makes

LED D7 to glow. The circuit diagram of the water level controller is shown in the figure below.


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Fig. 4.1 8051microcontroller Fig. 4.2 Battery level indicator

Fig. 4.3sensors arrangement for conditional based water pumping


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LM3914.

The heart of this circuit is the LM3914 from national semiconductors. The LM3914 can sensevoltage levels and can drive a display of 10 LEDs in dot mode or bar mode. The bar mode and

dot mode can be externally set and more than one ICs can be cascaded together to gat an

extended display. The IC can operate from a wide supply voltage (3V to 25V DC). The

brightness of the LEDs can be programmed using an external resistor. The LED outputs of

LM3914 are TTL and CMOS compatible.

Description

In the circuit diagram LEDs D1 toD10 displays the level of the battery in either dot or bargraph

mode. Resistor R4 connected between pins 6,7 and ground controls the brightness of the LEDs.

Resistors R1 and POT R2 forms a voltage divider network and the POT R2 can be used for

calibration.

The circuit shown here is designed in order to monitor between 10.5V to 15V DC. The

calibration of the circuit can be done as follows. After setting up the circuit connect a 12V DC

source to the input. Now adjust the 10K POT to get the LED10 glow (in dot mode) or LEDs up to

10 glow (in bar mode). Now decrease the voltage in steps and at 10.5 volts only LED1 will glow.

Switch S1 can be used to select between dot mode and bar graph mode. When S1 is closed, pin9

of the IC gets connected to the positive supply and bar graph mode gets enabled. When switch S1

is open pin9 of the IC gets disconnected to the positive supply and the display goes to the dot

mode.

With little modification the circuit can be used to monitor other voltage ranges. For this just

remove the resistor R3 and connect the upper level voltage to the input. Now adjust the POT R2

until LED 10 glows (in dot mode). Remove the upper voltage level and connect the lower level to

the input. Now connect a high value POT (say 500K) in the place of R3 and adjust it until LED1

alone glows. Now remove the POT, measure the current resistance across it and connect a resistor

of the same value in the place of R3. The level monitor is ready.


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CHAPTER -V

ADVANTAGES, APPLICATIONS AND FUTURE

ENHANCEMENT5.1 Advantages:

a. Stand-alone power station.b. Hybrid power generation i.e. combination of solar and wind based electric power

production.

c. Hybrid power supply from battery or directly from power line to D.C and A.Cappliances.

d. Eco-friendly.e. Easy to charge.f. Easy power generation.g. Low operating cost.h. High power quality.i. Automated control for pumping system.

5.2 Future Enhancement :a. Capital cost.

b. Environmental changes.c. Battery replacement after several cycles.

5.3 Applications :a. Remote places.

b. Irrigation.c. Domestic.d. Can be used for DC and AC appliance.

Documents

hybrid energy project