PV TECHNIQUES

SAURABH SINGHSCHOLAR NUMBER-152118214

M TECHMANIT, Bhopal

PV TECHNIQUE A methodology that is used to convert high

energy solar photons into electricity. Sun is a source of vast energy due to the

nuclear fusion reaction occuring continuously. The utilisation of this energy for the benefit

of the human beings plays a very crucial role in sustainable development…

PV TECHNIQUE The word PV can be abbreviated as P-PHOTON V-VOLTAGE Thus all the technologies that helps in the

conversion of solar photons into voltage(electricity) can be classified into pv techniques.

UTILIZATION OF SOLAR ENERGY Three techniques are involved in this

process.1. Solar energy collection2. Solar energy utilization3. Solar energy storage

SOLAR ENERGY COLLECTION The most important task of utilizing solar

energy is its collection. For this purpose solar collectors are used. Mainly classified into three types1. Solar flat plate collectors2. Concentrating type collectors3. Evacuated Solar collector

FLAT PLATE COLLECTOR

FLAT PLATE COLLECTOR Flat-plate collectors are used extensively for

domestic water heating applications. Hot water from this collector can be utilised as

boiler feed water in hybrid thermal systems and hence can be utilised to generate electricity..

It is simple in design and has no moving parts so requires little maintenance.

It is an insulated, weatherproofed box containing a dark absorber plate under one or more transparent covers.

They collect both direct and diffuse radiation. Their simplicity in construction reduces initial

cost and maintenance of the system.

CONCENTRATING TYPE COLLECTOR

CONCENTRATING COLLECTOR Concentrating collectors use mirrored

surfaces to concentrate the sun's energy on an absorber called a receiver.

A heat-transfer fluid flows through the receiver and absorbs heat.

These collectors reach much higher temperatures than flat-plate collectors

But they can do so only when direct sunlight is available.

However, concentrators can only focus direct solar radiation, with the result being that their performance is poor on hazy or cloudy days.

EVACUATED SOLAR COLLECTOR

EVACUATED SOLAR COLLECTORS Evacuated-Tube Collectors are made up of rows of

parallel, transparent glass tubes. Each tube consists of a glass outer tube and an inner

tube, or absorber, covered with a selective coating that absorbs solar energy well but inhibits radiative heat loss.

The air is withdrawn (―evacuated‖) from the space between the tubes to form a vacuum, which eliminates conductive and convective heat loss.

They are most suited to extremely cold ambient temperatures or in situations of consistently low-light.

They are also used in industrial applications, where high water temperatures or steam need to be generated where they become more cost effective

SOLAR ENERGY UTILIZATION Now after collection of solar energy next task

is the effective utilization of this energy for maintaining the comfort level of human beings.

This energy collected in the form of high temperature water can either be converted into electricity or can be used directly for both individual as well as industrial applications.

Includes1. Direct method2. Indirect method

SOLAR CELL Direct conversion of solar energy into

electricity is made possible with the help of a solar cell.

Can be classified into three types.1. Crystalline silicon solar cell2. Thin film solar cell3. Dye synthesised solar cell

WORKING OF SOLAR CELL

HOW SOLAR CELLS WORK

http://en.wikipedia.org/wiki/File:Silicon_Solar_cell_structure_and_mechanism.svg

1. Photons in sunlight hit the solar panel and are absorbed by semiconducting materials, such as silicon.

2. Electrons (negatively charged) are knocked loose from their atoms, allowing them to flow through the material to produce electricity.

3. An array of solar cells converts solar energy into a usable amount of direct current (DC) electricity.

CRYSTALLINE SILICON SOLAR CELL FIRST GENERATION SOLAR CELLS Classified into monocrystalline silicon solar

cell and poly crystalline solar cell.. Efficiency is in the range of 13% to 16%. Life is 25 years. Can only be used in clear sky days.

THIN FILM SOLAR CELL Materials Used1. Amorphous silicon solar cell2. CDTE. EFFICIENCY- 6% TO 8% LIFE- 15 years TO 20 years Can be used both in cloudy as well as hazy

days effectively. SECOND GENERATION SOLAR CELLS

DYE SENSITIZED SOLAR CELLS THIRD GENERATION SOLAR CELLS Can use any amount of light for conversion

into electricity Effciency- Very less about 3% to 4%. Life- 3 to 4 years Can be used effectively in any day of any

season

RANKINE CYCLE It is an indirect method of conversion of solar

energy into electricity. The high temperature water obtained from

CONCENTRATING TYPE COLLECTORS can be used as boiler feed water heater in hybrid solar thermal systems.

RANKINE CYCLE

RANKINE CYCLE The solar energy after heating the water in

the collector can be used as a source of heating for boiler.

Thus the steam obtained from this process can be utilized to run a turbine coupled to a generator which in turn generates electricity.

SOLAR ENERGY STORAGE Another problem associated with solar energy is

its storage. Solar energy is vast and numerous but it is of

highly varying nature. Hence its storage is must for its effective and

continuous utilization Energy storage devices like battery and capacitors

can be used for this purpose

THESIS Enhancing the efficiency of a system utilizing

pv technique

REVIEW The efficiency of any PV system is given as work

done/heat supplied. Thus for the same efficiency of the system work output

can be increased by enhancing the amount of solar energy absorbed.

Therefore focus must be laid on enhancing the collector efficiency.

ENHANCING THE COLLECTOR EFFICIENCY

Tilting the collector according to the latitude of the place where it is placed will increase the absorption of solar energy incident over it.

Tracking the collector along with the motion of the sun. Using corrugated or rough surfaces on the surface of the

collector instead of smooth surfaces.

CONCLUSION PV techniques not only refer to effective

conversion of solar energy into electricity but also refers to all the processes where effective utilization of solar energy is possible.

Devices like Solar cooker , Solar furnace , Solar green house , Solar dryer , Solar distillation , Solar thermo mechanical systems , Solar water heater are all parts of PV techniques only.

REFERENCES [1] D. Mills Advances in solar thermal electricity

technology. Sol Energy, 2004;76:19–31. [2] V.M. Nguyen, P.S. Doherty and S.B. Riffat, Applied

Thermal Engineering, Vol. 21(2001), p. 169. [3] J. Li, G. Pei and J. Ji, Appl. Energ. Vol. 87 (2010) p.

3355. [4] S. Quoilin, M. Orosz, H. Hemond and V. Lemort, Sol.

Energy Vol. 85 (2011) p.955 [5] Dilip Johari , Ashok Yadav, Ravi Verma ―Study of

solar water heaters based on exergy analysis‖ Proceedings of the National Conference on Trends and Advances in Mechanical Engineering,YMCA University of Science & Technology, Faridabad, Haryana, Oct 19-20, 2012.

REFERENCESo [6] Soteris A. Kalogirou, ―Solar thermal collectors and

applications.‖, Progress in Energy and Combustion Science 30 (2004) 231–295.

[7] Mustafa AKTAẞ, Olhan CEYLAN,Hikmet DOĞAN ― The Thermal Effectiveness Compression Of The Classical And Finned Solar System‖ Isı Bilimi ve Tekniği Dergisi, 26, 2, 29-33, 2006. J. of Thermal Science and Technology ©2006 TIBTD Printed in Turkey ISSBN 1300-3615.

[8] Samara Sadrin , Maherin Hossain , Ehsanul Mohith , ―Alternative solar water heater for domestic purpose‖.

REFERENCES

[9] P. Rhushi Prasad, H.V. Byregowda, P.B.Gangavati, ―Experiment Analysis of Flat Plate Collector and Comparison of Performance with Tracking Collector‖ European Journal of Scientific Research, ISSN 1450- 216X Vol.40 No.1 (2010), pp.144 -155, EuroJournals Publishing, Inc. 2010.

[10] R. Herrero Martín, A. García Pinar, J. Pérez García ―Experimental heat transfer research in enhanced flat-plate solar collectors‖, World Renewable Energy Congress -2011, Sweden.

[11] K. Sivakumar, N. Krishna Mohan and B. Sivaraman ―Performance analysis of elliptical heat pipe solar collector‖ Indian Journal of Science and Technology.

[12] Wattana Ratismith, ―A Novel Non-Tracking Solar Collector for High Temperature Application.‖, proceedings of ecos 2012 - the 25th international conference on efficiency, cost, optimization, simulation and environmental impact of energy systems June 26- 29, 2012, Perugia, Italy.

[13] P. Sivakumar1, W. Christraj, M. Sridharan1 and N. Jayamalathi1,‖Performance Improvement Study Of Solar Water Heating System‖, ARPN Journal of Engineering and Applied Sciences, VOL. 7, NO. 1, January 2012, ISSN 1819-6608.

[14] K.K. Chong, K.G. Chay, K.H. Chin, ―Study of a solar water heater using stationary V-trough collector‖, Renewable Energy 39 (2012) 207-215.

[15] S.Sadhishkumar T.Balusamy ―Performance improvement in solar water heating systems‖—A review Renewable and Sustainable Energy Reviews 37(2014)191

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