This document presents a summary of a student's research project on solar stills. It introduces solar stills as a method for purifying saline water using solar energy. It provides a brief history of solar stills, describes how they work through evaporation and condensation, and compares different types. The student's research is summarized as testing three solar still models with different water levels to determine maximum productivity. The conclusion is that less water in the still basin leads to higher efficiency. Solar stills provide an economical way to obtain drinking water in locations without other sources.

1. Presented By :-
Divyanshu Prakash Yadav
Roll No. :- CSJMA14001390235
B.Tech (Chemical Engg.)
CSJM University Kanpur
Submitted To :-
Dr. Brishti Mitra
HOD of Chemical Engg.
CSJM University Kanpur
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2. ABSTRACT
 Introduction.
 History of Solar Still.
 Solar water distillation technology.
 Solar Still.
 Quantity of distilled water.
 Efficiency.
 Advantage and disadvantage.
 A published journal.
 Conclusion.
 References.
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3. INTRODUCTION
 There are many coastle places where seawater is
sufficient but drinking water is not available.
 'WHO' states that almost 1 billion people are
drinking impure water and 2 million people die
every year due to unsafe water.
 To solve this problem use 'SOLAR STILLS'
based on 'SOLAR DISTILLATION PROCESS'.
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4. HISTORY OF SOLAR STILL
 First solar still was built by
Carlos Wilson in 1872 in
Chile.
 First time mass production
of 2,00,000 plastic stills by
U.S. navy during second
world war.
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5. SOLAR WATER DISTILLTION
TECHNOLGY
 This technology were built
over 2000 years ago.
 This is used where there is
no local source of fresh
water.
 This process is mimic of
the natural process of rain
formation.
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6. CONTINUE…
 It is described in two steps:-
 (1)- Evaporation.
 (2)- Condensation.
 This process removes water from
contaminant salts, heavy metals, sand and
microbiological organisms.
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7. SOLAR STILL
WHAT’S IT-
 It is a device, use for
purification of salty water.
 It is based on ‘solar water
distillation’ principle.
 It is cost-effective for small
scale production.
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8. HOW IT IS WORK
 The brackish water
poured into the still
partially.
 The solar radiation to
pass into the still, mostly
absorbed by blackened
base.
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9. CONTINUE..
 The water begins to heat up and
‘evaporation’ starts.
 The base also radiates energy which
reflected back into the still by the glass
cover, like ‘greenhouse’ effect.
 Condensation working.
 Still will continue produce distillate after
sunset until water temperature cools down.
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10. TYPE OF SOLAR STILL
Exe- Single Slope,
Double slope
still and single
and multi based
still
Passive
Solar Stills
Active Solar
Stills
Two Type
Exe- Solar Heater,
Novel Waste Heat.
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11. QUANTITY OF STILL WATER
PRODUTION
Solar still production is function of solar energy and ambient
temperature.
Productivity of solar still depends on climatic parameters.
Formula: - Me = Qe / L
Me= Daily distilled water output(kg/m2 day)
Qe= Amount of energy utilized in vaporizing
water in still (j/m2 day)
L = Latent heat of vaporization of water (j/kg)
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12. ANOTHER METHOD:-
An empirical relation given by Schumacher Center For
Technology UK.
Q = A × E × G / 2.3
Where ;
A= Aperture area of the still ; 1 meter square
E= Efficiency of the still ; usually taken as 50%
G= Global radiation energy ;18MJ/m2
Q=1 ×0.5 ×18.0 / 2.3 = 3.91
Daily output = 3.91 liters/meter square/day.
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13. EFFICIENCY
 It is the amount of energy utilized in vaporizing water
in the still(J/m2/day) over the amount of incident solar
energy on the still(J/m2/day).
 n = Qe /Qt
 All commercial stills sold have had an efficiency range
of 30% to 45%. Maximum efficiency is just over 60%.
 Solar still productivity can also increase by use of
mirror by 3%.
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14. HOW TO INCREASE
EFFICIENCY
 High feed (undistilled) water temperature.
 Large temperature difference b/n feed water and
condensing surface.
 Reducing heat conduction through basin walls vapour
leakage.
 Use of mirror.
 Insulation.
 Black liner.
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15. ADVANTAGES & DISADVANTA-
GES
ADVANTAGES DISADVANTAGES
 Low production capacity.
 Solar distillers can’t kill
harmful bacteria because it
do not boil the water.
 Leakage of vapour through
joints.
 Sun energy is free of
charge.
 Cost effectiveness since
there is no moving part so
low maintenace cost.
 Provide good quality water
for personal and industrial
use.
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16. A RESERCH PAPER ON
SINGLE SOLAR STILL
OBJECTIVE:- To find the potential , water depth
of a solar still basin.
DESIGN OF STILL:-
 We designed three
similar size solar still basin.
 This the schematic diagram.
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17. CONTINUE…
 First solar still M1(modle1)
 Second still M2
 Third still M3
 We add 3 liter brackish
water in M1.
6 liter of water in M2.
9 liter of water in M3.
Fabrication of these still in fig.
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18. MEASUREMENTS
 Table(1)- Ambient temperature, distilled water, solar
radiation as a function of time.
Data taken on 14-11-2010 from 6 am to 5 pm.
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19. CONTINUE….
 Ambient Temperature
variation:-
 Solar radiation
variation:-
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20. CONTINUE…
 Distilled water
at location:-
 Accumulated quantity
of distilled water
in three model :-
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21. RESULTS
 Daily output of three
tested Solar Still Basins.
M1 distilled more water.
 Lesser the amount of water placed in still basin (water
depth) then higher will be the efficiency of solar still.
 Efficiency :- M1 > M2 > M3
(NOTE- Data from research paper of Salem and Ghassa at Damascus
University)
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22. CONCLUSION
 It gives most economical method to get potable drinking water at
small scale.st
 The water that is made in these stills is of a better quality than
bottled water.
 Solar still device may uses in emergency situations life hurricane
or If water & electricity supply stopped, this may save our life.
 It produces most pure water similar to rainy water.
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23. REFERENCES
 https://www.hindawi.com/
 http://www.solaqua.com/
 https://en.wikipedia.org/wiki/Solar_still
 https://archive.org
 http://www.appropedia.org
 Manual on solar distillation of saline water
by Talbert, Eibling.
 https://www.scirp.org/journal/PaperInformation.asp
x?PaperID=29104
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