SOLAR PHOTO VOLTAIC CONVERSION SYSTEMS(Arjun Sibi)

1. SOLAR PHOTO VOLTAIC
CONVERSION SYSTEMS
Post-graduate Studies
Department of Mechanical Engineering
Mar Athanasius College of Engineering
Kothamangalam
october 2017 ARJUN SIBI
S1 THERMAL
ROLL NO:08

2. CONTENTS
 INRODUCTION
 PHOTOELECTRIC EFFECT.
 DESIGNING FACTORS
 WORKING
 ADVANTAGES
 DISADVANTAGES

3. INTRODUCTION
PV Conversion Systems ?
 Solar power is the conversion of sunlight into electricity, through
directly using photovoltaic PV cells by photoelectric effect.
 Commonly known as “solar cells”.
Photoelectric Effect ?
 The photovoltaic effect is the creation of voltage or electric
current in a material upon exposure to light

4. DESIGNING FACTOR
 Where to use the solar system.
 How about the solar irradiation condition in the area.
 Total loading power (KW).
 Daily consumption (KWH).
 System output voltage required.

5. MATERIALS
Crystalline Silicon
Cadmium Telluride
Copper Indium Gallium Selenide

6. WORKING

7. A standard PV cell is a thin semiconductor maid by doping process.
Doping Elements commonly used,
Silicon Dopants
p-type:- Boron , Gallium
n-type:-Phosphorus, Bismuth

8.  The p-n junction is effectively an interface between n and p
obtain By doping using Phosphorus atom
 The outer shell of a Phosphorus atom having five electrons in its
outer shell.

9. For each phosphorus atom that bonds with an adjacent silicon
atom there is an excess electron.
When a photon of light meets a doped silicon-phosphorus pair
the weakly bonded,‘ excess' phosphorus electron breaks and free.
The free and mooving of electrons through the silicon lattice
creates a weak electrical current and an electrical potential.

10. The solar module is combination of various solar cells that are
arranged in a specific pattern to convert sunlight in to power.
The number of cells in the solar module depends on the amount of
energy that is to be Generated.

11. STEPS OF FABRICATION
 The first practical photovoltaic cell was developed in 1954 at Bell
Laboratories that reached only 6% efficiency.
 Starts with locating a source of silicon dioxide in the form of sand
Silica (SiO2).
 First step is refining silica.
 Use hyper pure silicon for photovoltaics cell.

12. The silica is reduced (oxygen removed) through a reaction with
carbon in the form of coal or charcoal and heating to 1500-2000 °C
in an electrode arc furnace.
Silicon di oxide + Carbon =
Silicon + Carbon di oxide

13. The resulting silicon is 98% pure. It contains Fe, Al, and B.
Remove these traces , Powdered Si is reacted with anhydrous
HCl at 300 °C to form SiHCl3.
Si + 3HCl SiHCl3 + 2H2
 During this reaction impurities such as Fe, Al, and B react to
form their halides (e.g. FeCl3 , AlCl3 , and BCl3).

14.  Finally, the pure SiHCl3 is reacted with hydrogen at 1100 °C for
200 – 300 hours to produce a very pure form of silicon.
HSiCl3 + 2H2 2Si+6HCl
 Above reaction takes place inside large vacuum chambers and
the silicon is deposited onto thin polysilicon of diameter 150-
200mm.
 Different methods of solar cells fabrication are applied , each
method involves doping of silicon to make p-n junction , and
required processes to make a furnished solar cell.

15. METHODS OF FABRICATION
SCREEN PRINTED SOLAR CELL FABRICATION
CHNOLOGY
 It involves cutting a wafer of 10*10 square cm ,0.5mm thick ,
this wafer is then p-type doped with born to add up holes .
 Heating of wafer in a furnace about 800-1000 ºC with a
phosphorus atoms

16. BURIED CONTACT FABRICATION TECHNOLOGY
A groove is made by laser beam.
Heavy phosphorous diffused in side the grove.
This cell have performance up to 25% better than screen-printed
solar cells.

17. STRUCTURE

18. PRACTICAL SOLAR CELLS
Crystalline Silicon Cells Dominate
 To reduce the cost, these cells are now often made from
multi crystalline material, rather than from the more
expensive single crystals.
 The modules have long lifetime (20 years or more) and
their best production efficiency is approaching 18%.

19. Cadmium Telluride.
 Thin-film modules are now beginning to appear on the
market and hold the promise of combining low cost with
 Acceptable conversion efficiencies.
Gallium Arsenide.
 High-efficiency solar cells from, indium phosphate or their
derivatives are used in specialized applications,
 Power satellites or in systems which operate under high-
intensity concentrated sunlight.

20. ADVANTAGE
photovoltaic systems provide an increasingly attractive
alternative for electricity supply in part.
High reliability.
Low maintenance requirement.
Long Life Time.

21. DISADVANTAGES
At present the costs of solar cells are high, making them
economically uncompetitive with other conventional
power sources.
The efficiency of solar cells are low.
Large no. of solar cell modules are required to generate
power.
As solar energy is intermittent, some kind of electrical
energy storage is required, which makes the whole
system more expensive.

22.  Grid-Interactive PV Power generation
 Water pumping for the purpose of drinking or for irrigation
during the sunshine hours.
 Can meet low energy demands of many remote, small, isolated
villages.
 Solar PV panel are ideally suited for Telecommunication and
Signaling Applications such as local telephone exchange, radio and
TV broadcasting.
SOLAR PV APPLICATIONS

23. THANK YOU...