SOLAR DISTILLATION

On Tuesday, 9 April 2013

Presented by : Mrs. Kamala Soppin M.Sc, M.Phil

Asst. Prof. of PhysicsDRM Science college, Davangere, Karnataka.

Email: kamalasdrm@gmail.com

NATIONAL CONFERENCE ON SOLAR ENERGY AND ITS APPLICATIONSAT

MAHARANI’S SCIENCE COLLEGE FOR WOMEN, BANGALORE.

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Now a days the nuclear and solar energy are the most significant. Nuclear energy requires advance technology and costly means for its safe. But solar energy does not require high technology and there are no polluting effects.

Sources of energy1) Petroleum2) Natural gas3) Coal 4) Wood

Non renewable sources are consumed, we move towards search for a permanent type of energy resources.

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INTRODUCTIONINTRODUCTION

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The solar power which hits the earth’s surface about 1016 watts.

1013 watts needs of the world civilization. Therefore sun gives 1000 times more power than we need. A small amount of energy could be used for many important

uses. Solar energy is used in two methods. a) Thermal b) Photovoltaic (PV) Thermal energy is used for

Space heating and cooling, Cooking Water or air heating, drying of food grains, fruits, vegetables, cloths and purification of brackish water etc.,

PV solar cells are used for electric power generation

SIGNIFICANCE Solar energy is freely available in nature and also pollution free. It can be used in decentralized manner, reducing the cost of transmission and distribution

of power. Fresh and pure water is necessity for the sustenance of life and also key to man’s

prosperity. It is essential to provide pure and safe drinking water. The pure water can be obtained by distillation process i.e., in the simplest solar still. Such solar stills have been operated for the community use in the several countries.

TARGET AREA Davangere

Georgaphical coordinates of Davangere are 140 28’

North , 750 55’ East.

Davangere taluk has 936.6 sq. km area and has a

population about 4.62 lakhs.

It has approximately 300 days of bright sunshine

per year.

The average temp ranges between 260 to 380 C.

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Solar Distillation

The process of getting pure water by solar thermal

energy is called solar distillation.

For this process stills are used, which are based on the

principle of evaporation and condensation of water by

solar thermal energy.

Background information & Research

Germany is the world’s largest consumer of solar energy. Here 3800 Mw of solar power is produced.

Other consumers are Spain, Southern Portugal & North America.

USA & Srilanka already adopted solar distillation process at coastal and remote areas.

In Kerela, solar distaillations are used in farming and also in domestic purpose.

In Karnataka 3 Mw solar power plants already established at Kolar in 2010.

India is in the 7th place in the production of PV cells and in 9th place in solar thermal systems.

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Schematic diagram of solar still

Solar still consists of blackened basin containing impure water at a shallow depth, over which a transparent air tight cover encloses the basin. This glass cover is slopped down towards the collection trough.

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DESIGNING

• Working : Solar radiation passes through the cover is

absorbed and converted into heat in the black

surface. Impure water in the basin is heated and

vapour produced is condensed to purified water in

the cooler interior of the roof.

• The transparent roof materials transmits nearly all

the radiations falling on it and absorbs very little.

Hence it is cool enough to condense the water

vapour. The condensed water flows down the sloping

roof and collected in trough at the bottom.

The solar distilled unit consists of 3 parts :

1) Parallel plate collectors

2) Solenoid valve

3) Solar still

•There are three parallel plate collectors arranged in series.•These are made up of copper sheets and copper tubes. •The copper sheets and tubes are selectively coated to absorb more heat from the sun. •They are used to increase the temperature of water.•The temperature of water attains up to 800cCold water enters from overhead tank to bottom of the first collector and water gets heated up by solar energy. Due to density difference it rises its own in the copper tubes. This warm water enters the second collector and further heated up. This hot water enters into the third collector their it attains the temperature of about 800C. Rising the temperature of water before it enters the still basin is one of the most efficient ways to greatly increase the productivity of a solar still.

The size of each parallel plate collector is 2 m in length and 1 m in breadth. Each plate consists of 9 copper tubes of 1cm radius.

Parallel plate collectors

It is a sensor valve. It works from the low volt battery,

which is connected from external source (or AC mains). It is

fitted at the top end of the third collector. It is used to control

hot water release and is set at 800C, i.e, when the water at the

third parallel plate collector attains 800C the valve gets

opened and hot water from the collector enters into the solar

still basin.

Solenoid valve

It is the main part of solar distilled unit. It consists of blackened basin containing impure water at a shallow depth, over which a transparent air tight cover encloses the basin. The glass cover is a sloped down towards a collection trough.

Solar radiation passes through the cover is absorbed and converted into heat in the black surface. Impure water in the basin is heated and the vapors produced is condensed to purified water on the cooler interior of the roof. The transparent roof material transmits nearly all the radiation falling on it and absorbs very little, hence it remains cool enough to condense the water vapours. The condensed water flows down the sloping roof and is collected in troughs at the bottom.

The length and breadth of the solar still is about 1m x 1m. The depth is about 0.2m at one end. Still inclination should be

300 to 450 for better performance. This gives about 80 ltrs of pure drinking water per day.

Solar still

SCHEMATIC DIAGRAM OF SOLAR DISTILLATION UNIT

Installed solar distilled unit at DRM Science College, Davangere.

• Solar stills are effective in removing salts, bacteria

parasites and heavy metals. Stills are effectively purify

sea & sewage water. During rainy season still the

process is very effective for condensation of rain

water. Up to 90% of input water is recovered by

distillation process. The production rate depends on

the amount of solar radiation available, air,

temperature, wind speed, atmosphere humidity & sky

conditions etc. • Solar stills of size 20 sq.ft. will give about 6 to 8 ltr

pure drinking water per day.

• In the present research work, the water is purified using

solar stills which are based on the principle of evaporation

and condensation of water by solar thermal energy.

SUMMARY

Clean drinking water remains one of the most challenging international health issues of today, and solar distillation offers important and effective solutions in meeting potable water needs. Low cost solar stills offer an immediate and effective solution in reliably providing safe drinking water year after year. Single-basin solar stills are easy to build, inexpensive and extremely effective in distilling water with a high total dissolved salt content and in killing bacteria such as cholera and E. Coli. Single basin solar stills can use commonly available equipment, based on proven solar still designs.Average water production is about 0.8 liters per square meter per sun hour. Solar stills can bring immediate benefits to their users by alleviating chronic problems caused by water-borne diseases. Solar stills offer the only realistic and cost-effective means to provide safe drinking for many Borderland colonies residents who have few other realistic and affordable options available. Likewise, solar stills have tremendous potential worldwide in economically addressing rural potable water needs and in saving lives. water supplies grow increasingly scarce and more difficult to purify (i.e., increasing salinity), solar distillation offers a practical, effective, and relatively inexpensive means for residents to purify their drinking water. It can be practically applied on a decentralized and immediate basis by any end-user around the globe.

CONCLUSION

Energy is the backbone of technology & economic development. Rapid increase in use of energy has created problems of demand & supply. Also India has had a negative Energy Balance for decades. The Ministry of Power has set an agenda of providing Power to all. India can meet all energy needs with Renewable Energy Sources.

Solution to long-term energy problems will come only through research, development & implementation of such developments in the field of renewable energy sources. The total estimated potential of renewable Energy is around 152,000 MW, which is much greater than the current total installed energy generating capacity of India. To overcome energy crises, Government has developed many projects & programs for proper utilization of renewable energy resources. Energy problem is a global problem. Only the government cannot do everything. However individual & co-operative efforts can do a lot. So let us all work together to meet all energy needs of India.

REFERENCE

• Solar energy utilization – G.D. Rai • Non-conventional sources of energy - G.D. Rai • Solar distillation – State of the Art and future prospects • Understanding solar stills – Horace McCracken Joel Gordes. • Ministry for Non-conventional Energy Sources, commonly known as MNES • www.indiacore.com • www.kredl.kar.nic.in • www.energyglobe.com • "Mega power plants in AP and wind power in Orissa". Projectsmonitor.com.

http://www.projectsmonitor.com/ • Robert E. Foster Sharon E , Solar World Congress, International Solar Energy

Society Orlando, Florida, August 11, 2005 • epsea.org • www.zone water.net