A PROJECT REPORTON

SOLAR AIR COOLER AND HEATER WITH AUTOTRACKING

CONTENTS

▪ PROJECT OBJECTIVE

▪ UTILISATION OF SOLAR POWER

▪ PHOTOVOLTAIC METHOD

▪ COMPONENTS AND DESCRIPTION

▪ WORKING PRINCIPLE

▪ AUTOTRACKING MECHANISM

▪ CONCLUSION

▪ SCOPE OF IMPROVEMENT

▪ REFERENCE

Our objective is to design and develop a solar system normally “SOLAR AIR COOLER & HEATER WITH AUTO TRACKING”.

Solar electricity is the technology of converting sunlight directly in to electricity. It is based on photo-voltaic or solar modules, which are very reliable and do not require any fuel or servicing. Solar electric systems are suitable for plenty of sun and are ideal when there is no main electricity. 

PROJECT OBJECTIVE

UTILISATION OF SOLAR ENERGY

▪ Solar energy can be utilized directly either by photo-voltaic method or thermal method.

▪ Energy conversion devices, which are used to convert sunlight to electricity by use of the photo-voltaic effect, are called solar cells or photo-voltaic cells.

DIRECT METHOD OF UTILIZATION OF SOLAR ENERGY:

PHOTO-VOLTAIC EFFECT

▪ The photo-voltaic effect is the creation of voltage or electric current in a material upon exposure to light.

When the sunlight or any other light is incident upon a material surface(conductors or semiconductors), the electrons present in the valence band absorb energy and, being excited, jump to the conduction band and become free. These highly excited, non-thermal electrons diffuse, and some reach a junction where they are accelerated into a different material. This generates an electromotive force, and thus some of the light energy is converted into electric energy.

COMPONENTS & DESCRIPTIONThe physical setup of this project consists of following components.

• Solar Panel• Battery(12 Volt DC)• Blower(DC motor coupled with impeller)• Water Pump

SOLAR PANEL

▪ A Solar panel consists of many solar cells.

▪ Solar cell, also called photovoltaic cell,  any device that directly converts the energy in light into electrical energy through the photovoltaic effect.A solar cell(photo-voltaic cell) works on the principle of photo-voltaic principle, the photo-voltaic solar energy conversion method is one of the most attractive method of utilization of solar power.

PHOTO-VOLTAIC CELL

▪ In photo-voltaic cell, the sensitive element is a semiconductor, which generates voltage in proportion to the light or any radiant energy incident on it.

▪ The most commonly used photo-voltaic cells are barrier layer type like iron-selenium cells or .

▪ It consists of a metal electrode on which a layer of selenium is deposited. On the top this a barrier layer is formed which is located with a very thin layer of gold. It serves as a translucent electrode through which light can impinge on the layer below. Under the influence of this light, a negative charge will build up on the gold electrode and a positive charge on the bottom electrode.

A number of solar cells electrically connected to each other and mounted in a support structure or frame is called a photovoltaic module. Multiple modules can be wired together to form an array. In general, the larger the area of a module or array, the more electricity that will be produced.

BATTERIES

Batteries are used for storage of solar energy. We use lead acid battery for storing the electrical energy from the solar panel. To be economically attractive the storage of solar electricity requires a battery with a particular combination of properties:

▪ Low cost

▪ Long life

▪ High reliability

▪ High overall efficiency

▪ Low discharge

▪ Minimum maintenance

BLOWER

▪ The fan (impeller) rotates inside the shell. The shell is so designed that the air is rushed out forcibly. The blower consists of two main parts. They are

▪ D.C motor

▪ Blades(fan)

▪ The D.C motor is directly coupled with Impeller blades. The water pump is used to circulate the water to the blower. The cool air is rushed out forcibly. The battery is connected to the D.C motor, so that D.C motor runs directly. The switch is connected to disconnect the water pumping system when the time of water  heater ON. The water heater has drawn the power from the single phase power supply.

The working principle tells that, when a current carrying conductor is placed in a magnetic field, a force is produced to move the conductor away from the magnetic field. The force given by the equation, 

F=B I L NewtonWhere,

B = Flux density in WB/sq.mI = Current through the conductorL = Length of the conductor

 

Dc motor connected to two blowers

NEED OF AUTOTRACKING

▪ To increase the efficiency of the system.

▪ To increase the power production in the solar panel by adding auto tracking mechanism.

WORKING PRINCIPLE

▪ Light Depending Resister (LDR) is used as a light sensor. The LDR output is given to the control circuit. The control circuit is used to activate/deactivate the relay circuit depends upon the input signal (i.e. output of LDR) of control circuit. Whenever the sun position changed, the control circuit is activated to the relay circuit.

AUTO TRACKING

 The Relay output is connected to the Permanent Magnet D.C. Motor (PMDC). The relay is activated, the Permanent Magnet D.C (P.M.D.C) motor starts running. The P.M.D.C motor coupled with chain drive to the solar panel. So the panel was tilting some angle depends upon the motor activating time. The solar panel was tilted according to the sun movement. So this mechanism is called “AUTO TRACKING MECHANISM”. 

WORKING PRINCIPLE

▪ The solar panel converts sun rays to the Electricity by “Photo-Voltaic Effect”. This electrical power is stored in a 12-Volt battery. Battery D.C power is used to run the D.C motor and D.C water pump.

▪ The D.C motor is coupled with impeller blades. The D.C motor runs during the air cooler button ON, the impeller blades starts rotating. The water pump is used to circulate the water to the blower unit.

▪ The forced air is then flow through the water which is sprayed by water pump, so that the cold air produced. The switch control is used to ON/OFF solar air cooler circuit and heater circuit.

CONSTRUCTION

ADVANTAGES  Simple in construction This system is noiseless in operation It uses non-conventional source of energy Power is stored in a battery Maintenance cost is low Heating and cooling operation are possible in a single system.

DISADVANTAGES It is not portable, so it can not be transferred easily from one place to other place Initial cost is high Solar panel saves the energy during day time only Low efficiency

REFERENCES

Wikipedia

Chemistry of Engineering materials by P.C. Jain.