20120140505015

International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN 0976 –
6480(Print), ISSN 0976 – 6499(Online) Volume 5, Issue 5, May (2014), pp. 125-140 © IAEME
125
FABRICATION AND ANALYSIS OF PORTABLE DESALINATION SYSTEM
Ananthan D Thampi1
, Ajith C Menon2
, Cedric Benedict3
, Amal Sreenivas4
1,3,4
Eighth Semester B.Tech Students, 2
Assistant Professor,
Department of Mechanical Engineering, Marian Engineering College,
Menamkulam, Kazhakuttom, Thiruvananthapuram Pin No: 695582
ABSTRACT
Water is nature’s gift and it plays a key role in the development of an economy and in turn
for the welfare of the nation. Scarcity of drinking water is one of the major problems faced all over
the world. Today, majority of the health issues are due to the scarcity of clean drinking water. In
recent decades, insufficient rainfall resulted in an increase in the water salinity. The water pollution
is increasing drastically due to a factors like population growth, industrialization, urbanization, etc.
Desalination is the oldest technology used by people for water purification. Various new
technologies were invented for desalination from time to time and it has been accepted by people
without knowing future environmental consequences. Major desalination techniques like distillation,
reverse osmosis and electrolysis used electricity as input energy. Now input is provided with the help
of solar energy so there will be no pollution and it’s free of cost. As the water inside the solar still
evaporates, it leaves all contaminants and microbes in the basin. The purified water vapour
condenses on the inner side of the glass, runs through the lower side of the still and then gets
collected in a closed container. Many solar distillation systems were developed over the years using
the above principle for water purification in many parts of the world. This is similar to rainwater
formation. So we decided to do a work based on solar still. We have fabricated a double slope solar
still along with a water heater which is controlled by a thermostat and a setup to measure power by
using wattmeter. Vacuum pressure gauge and Thermometer is used to measure pressure and
temperature inside the collecting tank respectively, a vacuum pump is also used to reduce pressure
inside the still.
Keywords: Solar Still, Desalination, Distillation.
INTERNATIONAL JOURNAL OF ADVANCED RESEARCH
IN ENGINEERING AND TECHNOLOGY (IJARET)
ISSN 0976 - 6480 (Print)
ISSN 0976 - 6499 (Online)
Volume 5, Issue 5, May (2014), pp. 125-140
© IAEME: www.iaeme.com/ijaret.asp
Journal Impact Factor (2014): 7.8273 (Calculated by GISI)
www.jifactor.com
IJARET
© I A E M E

126
1. INTRODUCTION
The shortage of drinking water is expected to be the biggest problem of the world in this
century due to unsustainable consumption rates and population growth. Pollution of fresh water
resources (rivers, lakes and underground water) by industrial wastes has increased the problem. The
total amount of global water reserves is about 1.4 billion cubic kilometers. Oceans constitute about
97.5% of the total amount, and the remaining 2.5% fresh water is present in the atmosphere, surface
water, polar ice and ground water. This means that only about 0.014% is directly available to human
beings and other organisms. Therefore, the development of new clean water sources is imperative.
Desalination of sea and/or brackish water is an important alternative, since the only inexhaustible
source of water is the ocean. Solar desalination is suitable for remote, arid and semi- arid areas,
where drinking water shortage is a major problem and solar radiation is high. These places mostly
suffer also from energy shortage. The limitations of solar energy utilization for desalination are the
high initial cost for renewable energy devices and intermittent nature of the solar radiation. Due to
these limitations the present capacity of solar desalination systems worldwide is only about 0.01% of
the existing large-scale conventional desalination plants. Therefore, efforts must be made to develope
technologies, which will collect and use renewable energy more efficiently and cost effectively to
provide clean drinking water. Besides, developing new technologies to store this energy for using it
whenever it is not available is also required. Solar stills are commonly used in arid coastal zones to
provide low-cost fresh water from the sea. Total daily output of the solar still decreases with
increasing water depth, but overnight output increases with an increase in water depth, which
contributes considerably towards the total daily output. However, various scientists have made
attempts to maximize the daily yield per square metre/day in a single basin solar still in a passive
mode. From the previous work, it has been observed that the daily yield per square metre /day in the
basin solar still mainly depends on the evaporative area and condensing surfaces.
The energy required to evaporate water, called the latent heat of vaporisation of water, is
2260 kilojoules per kilogram (kJ/kg).This means that to produce 1 litre (i.e. 1kg as the density of
water is 1kg/litre) of pure water by distilling brackish water requires a heat input of 2260kJ. This
does not allow for the efficiency of the system sued which will be less than 100%, or for any
recovery of latent heat that is rejected when the water vapour is condensed. It should be noted that,
although 2260kJ/kg is required to evaporate water, to pump a kg of water through 20m head requires
only 0.2kJ/kg. Distillation is therefore normally considered only where there is no local source of
fresh water that can be easily pumped or lifted. The objective of the present work is to fabricate a
working model of solar still with few modifications and do experimental analysis on the solar still.
2. BASIC PRINCIPLE OF SOLAR STILL
The basic principle behind solar distillation is simple and replicates the natural process of
water purification. A solar still is an air tight basin that contains saline or contaminated water (i.e.
feed water).It is enclosed by a transparent top cover, usually of glass or plastic, which allows
incident solar radiation to pass through. The inner surface of the basin is usually blackened to
increase the efficiency of the system by absorbing more of the incident solar radiation. The feed
water heats up, then starts to evaporate and subsequently condenses on the inside of the top cover,
which is at a lower temperature as it is in contact with the ambient air. The condensed water (i.e. the
distillate) trickles down the cover and is collected in an interior trough and then stored in a separate
basin. This system is also known as passive solar still, as it operates solely on sun’s radiation
From a radiative point of view the following happens inside the distiller unit: the part of the
solar radiation that is not reflected nor absorbed by the cover is transmitted inside the solar still,
where it is further reflected and absorbed by the water mass. The amount of solar radiation that is

127
absorbed is a function of the absorptivity and depth of the water. The remaining energy eventually
reaches the blackened basin liner, where it is mostly absorbed and converted into thermal energy.
Some of this energy might be lost due to poor insulation of the sides and bottom. At this stage, the
water heats up, resulting in an increase of the temperature difference between the cover and the water
itself. Heat transfer takes then place as radiation, convection and evaporation from the water surface
to the inner part of the cover. The evaporated water condenses and releases latent heat. This last one
is then lost through convection and radiation together with the remaining convective and radiative
heat.
Little research has been done regarding the water quality of the water produced by solar-
stills based on polluted or muddy water. However it is proven that nitrates, chlorides, iron, heavy
metals and dissolved solids are completely removed by the solar still. The process also proved to be
effective in the destruction of microbiological organisms present in the feed water. The distillate is
thus high purity water, which also lacks essential dissolved minerals. Drinking de-mineralised water
can have serious health consequences, and it is thus of crucial importance that the essential minerals
are added to the water before consumption. The advised quantities of minerals where minimum or no
adverse health effects are observed to be measured in the field. Once the working of the system has
proven to be effective, it is important that the water users are well informed about the solar still in
order to ensure its correct functioning and its sustainability. It is essential to emphasize that the solar
still will only produce the expected output when it is fully airtight. This means that the water inlet
should never be opened. The same holds for the drinking water tank which should also never be
opened.
3. LITERATURE REVIEW
Anirudh Biswas, Ruby in their paper discussed about clean water remains one of the most
challenging international issues of today and solar distillation offers important and effective
solutions. Low cost solar stills offers immediate and effective solutions in reliably providing safe
distill 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. Average water production of a single solar still is about 0.5 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
distill water for use. [1]
M.KoilrajGnanadson, P.Senthilkumar, G.Sivaraman in their paper discussed about a single
basin solar still made up of copper sheet was fabricated and tested for both the conditions with and
without vacuum.The distilled water production rate of a single basin solar still can be varied with the
design of the solar still, absorbing materials, depth of water, salt concentration and location. The
efficiency is higher for a solar still made up of copper and it can be increased further by painting
black inside the still. The modified innovative still working under low pressure has enhanced
performance in compared with the still working at atmospheric pressure and more flexible with
climatic conditions. Average requirement of water per person in a house is assumed to be around
1.5litres/day. Therefore it gives the total water consumption to be around 7.5 liters/day. Their design
is expected to be cost effective and provide an efficient way to convert the brackish water into
potable water.[2]
K.Sampathkumar, T.V.Arjunan, P.Pitchandi, P.Senthilkumar in their paper discussed about
the use of solar energy in desalination process is one of the best applications of renewable energy.
The solar stills are friendly to nature and eco-system. Various types and developments in active solar
distillation systems, theoretical analysis and future scope for research were reviewed in detail.[3]

128
A. E. Kabeel, based on the results obtained from their experimental work, the conclusions
from their results are the temperature of the four glass cover surface is not equally specially till
afternoon, the average distillate productivity of the proposed still during the 24 hours time is about
4l/m2
, the proposed solar still efficiency is 0.38 at solar noon. In order to complete the whole picture
of their study, a future work was proposed by them like studying the system theoretical
performance,studying the system at different glass tilt angles, studying the system at different water
depth in the still basin.[4]
Kaabi Abdennacer, Trad Rachid in their paper they discussed about the use of solar energy
for water desalination becomes necessary due to lack of water. In this case, they propose in their
study a model of a solar still with a collector having two slopes (double exposure).The system
collects a maximum of solar radiation. In order to render the system well performed, they optimised
in their study some thermo physical parameters which have a direct effect on its performance. The
obtained results concluded that a wind velocity going up to 10 m/s, affects directly the production of
distilled water and beyond this value (10 m/s),this production becomes insignificant, the angle of the
inclination of the collector (β) seems to be justified, where an optimum angle of 10° will give a better
production of distilled water, an increase of the temperature difference (δt) between the collector and
the basin water will bring the production of distilled water at its maximum, the ideal depth of the
basin water is at its minimum value, where in their case a water depth of 0.02 m will give a better
production of distilled water, an absorber made of aluminium covered by a black and thick layer in
order to give a better absorption of the solar radiation, leads to a better production of distilled water,
an insulator made of polystyrene and reinforced by a metallic or a wooden support will limit heat
losses.[5]
Hazim Mohameed Qiblawey, Fawzi Banat in their paper they have presented an overview of
solar thermal desalination technologies, focusing on those technologies appropriate for use in remote
villages. Solar energy coupled to desalination offers a promising prospect for covering the
fundamental needs of power and water in remote regions, where connection to the public electric
grid is either not cost effective or not feasible and where the water scarcity is severe. Solar
desalination processes can be devised in two main types: direct and indirect collection systems. The
“direct method” use solar energy to produce distillate directly in the solar collector, whereas in
indirect collection systems, two sub-systems are employed (one for solar energy collection and the
other one for desalination).The direct solar energy method uses a variety of simple stills which are
appropriate for very small water demands; indirect methods use thermal or electrical energy and can
be classified as: distillation methods using solar collectors or membrane methods using solar
collectors and/or photovoltaics for power generation. Solar thermal desalination plants utilizing
indirect collection of solar energy can be classified into the following categories:
Atmospheric humidification/dehumidification, Multi-Stage Flash (MSF), Multi-Effect
Distillation (MED), Vapor Compression (VC) and Membrane Distillation (MD).[6]
Prof.Nilamkumar S Patel, Prof.Reepen R Shah, Mr.Nisarg M Patel, Prof.J.K.Shah,
Mr.Sharvil B Bhatt from their paper it was concluded that after reviewing all type of solar stills. By
considering it is found that stepwise basin solar still gives much better as compared to all solar still
discussed above because of its large absorbing area or basin area. The efficiency of stepwise solar
still is higher than concave and conventional solar still. So, ascending order of efficiency of solar still
is [conventional solar still <concave solar still <pyramid solar still].[7]
Bilal A Akash, Mousa S. Mohsen, Waleed Nayfeh for the cases considered in their paper, an
optimum cover tilt angle of 350
was determined for maximum water production in the solar still
during the month of may. The salinity of water affects distillate production even at low
concentration. It decreases with increasing salinity. However, when the concentration is high, a
smaller decrease in productivity with increasing salinity is noticed in their experiments. Water depth

129
affects the amount of distillation. It decreases with increasing water depth in a somewhat linear
relationship.[8]
4. DESCRIPTION OF APPARATUS
For high efficiency the solar still should maintain a high feed water temperature, a large
temperature difference between feed water and condensing surface, low vapour leakage.
In this work, We have selected a double slope solar still instead of a single slope solar still, so
that the apparatus will be exposed to solar radiation for more time. The brackish water that is
provided into solar still basin can be heated, so we have provided a heating chamber inside which an
ordinary heater is placed and they can be controlled with help of a thermostat. When pressure inside
is reduced boiling point of water decreases, so we have also provided a vacuum pump to reduce
pressure. We have also provided measuring instruments to measure temperature, pressure, power.
4.1 Design of Solar Still
Fig 1: CAD drawing of proposed still, front view Fig 2: CAD drawing of proposed still, side view
Fig 3: 3D drawing of the proposed Fig 4: 3D drawing of the proposed
collecting tank with a heater double sloped Solar still

130
Fig 5: 3D drawing of both the collecting tank with heater and double slope solar still
5. MANUFACTURING AND ASSEMBLY
5.1 Material Selection
• Basin Liner: This is a major part of the solar still. It absorbs the incident solar radiation that is
transmitted through the glass cover. The basin liner should be resistant to hot saline water or
brackish water, has high absorbance to solar radiation and resistance to accidental puncturing
and in case of damage, it should be easily repaired. Black paint can be used to increase the
absorptivity of solar still.
• Mild steel: It is least expensive of all steels and most common steel used. It is weldable, very
hard, durable and also it is malleable and ductile. It contains 0.29% carbon. Due to its poor
corrosion resistance. It must be painted or otherwise protected and sealed in order to prevent
rust from damaging it. The thermal conductivity of mild steel is 43 w/mk. The cost of mild
steel is 53Rs/kg. Mild steel is used in our work.
• Glass Cover: In our work, glass of 4 mm thickness was used and its average transmissivity of
0.89, it was fixed at angle of 15o
. Glass cover has been sealed with silicon rubber, which is
most successful because, it will make strongly contact between the glass and many other
materials. The sealant is important for efficient operation.
• Insulating material: It is used to reduce the heat losses from the bottom and the side walls of the
solar still in this work. The insulating material is a rock wool of 5 cm thickness and 0.048
w/m20
c thermal conductivity and thermocol can also be used.
5.2 Steps of Manufacturing and Assembling
Fabrication of the whole unit is pretty straight forward and involves metal cutting, welding,
glass cutting, sealing, painting and drilling. All these processes can be done at any local workshops
using simple machines – lathe, drill, welding, milling etc. The steps in the process of manufacturing
and assembling are outlined as follows:
• Solar still basin will be fabricated first. It will be made of double wall and will be filled with
glass wool or thermocol to provide insulation and supports to place glass.
• The collector tubes are then made and attached to the still basin.
• The holes are provided for:
a. collecting distilled water
b. transporting saline water

131
c. to attach the pump
d. to clean the basin.
• The whole system is sealed using sealant to prevent the air from leaking in from the
atmosphere.
• Pipes and valves for each holes are provided.
• The whole system is then painted to prevent rusting.
• Glass required is cut and placed on the support and using silica gel it is fixed to the system.
• Vacuum pump and heating chamber are connected to solar still using flexible pipes.
The cost of construction for a passive solar still is considerably cheaper than a more complex
humidification/condensation flow through system. All that is required is a large insulated box with
solar absorbing material in the basin, a transparent glazing. Because the box is not under any loading,
most insulating foam boards such as expanded polystyrene, extruded polystyrene and
polyisocyanurate board can provide structural rigidity and no other materials will be needed.
6. EXPERIMENTAL SETUP
The solar still, the simplest desalination technology, consists of a shallow basin with a
transparent cover. Water in the basin, heated by the sun, produces vapour which condenses on the
cover, releasing its heat to the atmosphere and runs off the cover into a collecting trough. The
temperature difference between the water and the atmosphere needed to produce distillation at a
usable rate is about 5° to 10° C. The amount of water desalinated by the solar still depends on the
amount of solar insolation, area of the still, ambient air temperature, feed water temperature,
presence of insulation around the sides and bottom of the still, presence of leaks in the still, slope of
the cover with respect to the incidence angle of incoming sunlight and the depth of water in the still.
A primary advantage of solar stills is that they can be constructed from cheap, locally available
materials, such as wood, concrete, metal, thermocol, glass. The cover must be transparent to sunlight
but trap heat; therefore, glass or plastic is used. a sealant such as silicone prevents leaks. A dark
material such as butyl rubber is usually used to line the basin. Sand or Sawdust can provide
insulation. Maintenance of the still involves checking for and repairing leaks, periodic flushing to
remove salt deposits and cleaning of debris and dust from the cover.
The solar desalination system consist of a collecting tank where the saline water is initially
collected and stored. Provision for heating the water is provided in a heating chamber. This chamber
is connected with the desalination tank using a hose. The water flow is adjusted by a ball valve and a
float valve for controlling the water level inside the desalination chamber. Water enters the
desalination chamber through a hose. The desalination chamber is a double sloped solar still
arrangement. The slopes are equipped with glass. So as to trap the sunlight, to provide a condensing
surface and to obtain greenhouse effect. The condensing water drops down through the slope and it is
channeled to the outlet valve. The oulet valve is provided with a ball valve for obtaining the
condensed desalined water. The requirement of a ball valve is to seal the chamber from atmospheric
interference. The desalination chamber is provided with a nozzle for creating vacuum. The vacuum is
created using a vacuum pump
ଵ
ହ
HP pump, which can reduce the pressure. Finally a pipe is given for
flushing out the salt deposits. Measuring instruments are used to measure temperature, pressure,
power.

132
Fig 6: Solar still during Experimental analysis Fig 7: Water getting condensed in the Solar still
7. RESULT AND DISCUSSION
The experiments on the still was conducted from 10.00 AM to 6.00 PM. Experiments were
conducted with a basic solar still without any modifications, basic solar still with heater, basic solar
still with heater under reduced pressure. The experiments were conducted on the month of february
and march. Initially results were obtained without proper insulation and after that with proper
insulation. The readings of Atmospheric temperature (TA), Temperature of Water
inlet(TIN),Temperature of Water inside( TWI) are measured in terms of 0
C and Productivity was
measured in terms of ml. The results are tabulated below:
Table 1: variation on a Basic Solar Still without insulation
Graph 1: Productivity Vs Time plot for basic solar still without insulation
0
10
20
30
40
50
60
10:00…
11:00…
12:00PM
1:00AM
2:00PM
3:00PM
4:00PM
5:00PM
6:00PM
productivityinml
time of the day
productivity
SL TIME TA
ሺԨሻ ሺԨሻ
TIN
ሺԨሻ
TWI PRODUCTIVITY
(ml)
1 10am 32 32 34.1 0
2 11am 32 35 39.5 5
3 12pm 34 36 43.4 10
4 1pm 34 38 48.7 15
5 2pm 34 40 50.5 25
6 3pm 34 41 52.8 50
7 4pm 34 42 52.4 20
8 5pm 32 39 50.4 15
9 6pm 32 37 46.1 10
TOTAL 150ml

133
Graph 2: Temperature Vs Time plot for basic solar still without insulation
Table 2: variation on a basic Solar Still with Heater without insulation
Graph 3: Productivity Vs Time plot for basic solar still with heater without insulation
0
10
20
30
40
50
60
temperaturein⁰⁰⁰⁰C
time of the day
Atmospheric
temperature
temperature of
inlet water
temperature of
water inside
0
10
20
30
40
50
60
productivityinml
time of the day
productivity
SL TIME TA
ሺԨሻ
TIN
ሺԨሻ ሺԨሻ
TWI PRODUCTIVITY
(ml)
1 10am 32 32 47.7 20
2 11am 32 34 50.2 40
3 12pm 34 36 54.2 40
4 1pm 34 38 52 42
5 2pm 34 40 53.5 45
6 3pm 34 41 54.4 55
7 4pm 34 43 52.7 38
8 5pm 32 40 51.6 25
9 6pm 32 38 50.6 15
TOTAL 320ml

134
Graph 4: Temperature Vs Time plot of basic solar still with heater without insulation
Table 3: variation of a basic Solar Still with Insulation
Graph 5: Productivity Vs Time for basic solar still with insulation
0
10
20
30
40
50
60
temperaturein⁰C
time of the day
Atmospheric
temperature
Temperature of
water inlet
temperature of
water inside
0
50
100
150
200
250
productivityinml
time of the day
Productivity
SL TIME TA
ሺԨሻ ሺԨሻ
TIN
ሺԨሻ
TWI PRODUCTIVITY
(ml)
1 10am 32 32 34.1 30
2 11am 32 35 39.5 50
3 12pm 34 36 43.4 80
4 1pm 34 38 48.7 120
5 2pm 34 40 50.5 150
6 3pm 34 41 52.8 200
7 4pm 34 42 52.4 170
8 5pm 32 39 50.4 90
9 6pm 32 37 46.1 60
TOTAL 950ml

135
Graph 6: Temperature Vs Time plot for basic solar still with insulation
Table 4: variation on a basic Solar Still with Heater and Insulation
Graph 7 : Productivity Vs Time for basic solar still with heater and insulation
0
10
20
30
40
50
60
10:00AM
11:00AM
12:00PM
1:00AM
2:00PM
3:00PM
4:00PM
5:00PM
6:00PM
time of the day
Atmospheric
temperature
Temperature of
water inlet
Temperature of
water inside
0
50
100
150
200
250
300
productivityinml
time of the day
Productivity
SL TIME
ሺԨሻ
TA TIN
ሺԨሻ ሺԨሻ
TWI PRODUCTIVITY
(ml)
1 10am 32 32 52 55
2 11am 32 34 53 80
3 12pm 34 37 55 120
4 1pm 34 38 56 160
5 2pm 34 41 58 210
6 3pm 34 42 61 240
7 4pm 34 44 57 200
8 5pm 32 39 54 150
9 6pm 32 37 50 85
TOTAL 1300ml

136
Graph 8: Temperature Vs Time plot of basic solar still with heater and insulation
Table 5: variation on a basic Solar Still with Vacuum pump, Heater and Insulation
Graph 9: Productivity Vs Time for basic solar still with vacuum pump, heater with insulation
0
20
40
60
80
temperatureinoC time of the day
Atmospheric
temperature
Temperature of
water inlet
Temperature of
water inside
0
50
100
150
200
250
300
10:00AM
11:00AM
12:00PM
1:00AM
2:00PM
3:00PM
4:00PM
5:00PM
6:00PM
productivityinml
time of the day
Productivity
SL TIME
ሺԨሻ
TA
ሺԨሻ
TIN TWI
ሺԨሻ
PRODUCTIVITY
(ml)
1 10am 32 32 53 55
2 11am 32 35 54 80
3 12pm 34 37 54 120
4 1pm 34 39 56 180
5 2pm 34 41 59 220
6 3pm 34 42 60 260
7 4pm 34 43 58 210
8 5pm 32 39 55 155
9 6pm 32 36 51 90
TOTAL 1370ml

137
Graph 10: Temperature Vs Time plot for basic solar still with vacuum pump, heater with insulation
Graph 11: Productivity Vs Time plot at different setup
Graph 12: Temperature Vs Time plot of water temperatures with different setup
8. INFERENCE
From the readings we obtained in the basic still and basic solar still with heater, initially was
not up to the expected. So we gave additional insulation, thus the conduction losses where reduced.
The productivity was very low but after providing insulation the productivity was raised to about
900ml. The readings from basic solar still with heater and added insulation shows an increment in
0
10
20
30
40
50
60
70
time of the day
Atmospheric
temperature
Temperature of
water inlet
Temperature of
wter inside
0
50
100
150
200
250
300
productivityinml
time of the day
basic with
insulation
with heater and
insulation
with vacuum
pump heater
and insulation
0
10
20
30
40
50
60
70
10:00AM
11:00AM
12:00PM
1:00AM
2:00PM
3:00PM
4:00PM
5:00PM
6:00PM
time of the day
basic with
insulation
with heater
and
insulation
with vacuum
pump and
heater and
insulation

138
productivity with respect to the basic and by incorporating vacuum pump there is only a very small
increment in productivity. These readings may have varied due to
• Conduction losses
• Insufficient solar radiation
• Any small leak in the system
• Place where experiment was conducted.
9. COST EFFECTIVE ANALYSIS
The cost of pure water produced depends on:
• The cost of making the still
• The cost of the land
• The life of the still
• Operating costs
• Cost of the feed water
• The discount rate adopted
• The amount of water produced.
It is important that stills are regularly inspected and maintained to retain their efficiency and
reduce deterioration. Damage, such as breakage of the collector plate, needs to be rectified. Rain
water collection is an even simpler technique than solar distillation and is preferable in areas with
400mm of rain annually, but requires a greater area and usually a larger storage tank. If ready-made
collection surfaces exist (such as house roofs) these may provide a less expensive source for
obtaining clean water.
COST OF MATERIAL = Rs. 500
COST OF LABOUR = Rs. 1500
COST OF GLASS = Rs. 1000
COST OF VACUUM PUMP = Rs. 2500
COST OF HEATER = Rs. 300
COST OF ACCESSORIES = Rs. 3200
TOTAL COST = Rs. 9000
FOR BASIC SOLAR STILL WE ARE GETTING 950 ml/day: Thus for 1 year the output is
347L. Let us assume 15 Rs/L as the cost of water. Then Rs.5,205 will be the actual cost to buy this
much amount of water which is received for just Rs. 3500 by using our solar still. So within 8
months we are getting our money back and the remaining is profit.
FOR BASIC SOLAR STILL WITH HEATER WE ARE GETTING 1300 ml/day: Thus for 1
year the output is 475L.Let us assume 15Rs/L as the cost of water. Then Rs.7125 will be the actual
cost to buy this much amount of water which is received for just Rs.5600 by using our solar still with
heater. So within 10 months we are getting our money back and the remaining is profit.
FOR BASIC SOLAR STILL WITH HEATER AND VACUUM PUMP WE ARE GETTING
1370ml/day: Thus for 1 year the output is 500L. Let us assume 15Rs/L as the cost of water.Then
Rs.7500 will be the actual cost to buy this much amount of water which is received for justRs.8100
by using our solar still with heater and vacuum pump. So within 13 months we are getting our money
back and the remaining is profit.

139
There is a need for more water to drink so we suggest basic solar still with water heater is
more cost effective to use. A family of four requires a minimum output of 8L.Actually by using the
formula
Q=
ሺா‫כீכ‬஺ሻ
ଶ.ଷ
Where,
Q = daily output of distilled water (litres/day)
E = overall efficiency
G = daily global solar irradiation (MJ/m²)
A = aperture area of the still ie, the plan areas for a simple basin still (m²)
From the equation, The output for this solar still should be 1.2L/day based on the reading it is
correct. So by using heater our output was increased by more than 35%. So for producing 7L water
as output per day based on equation area, A need to be increased to 3.6m2
. So material required is 7
times thus cost of material and labour increases and will be about Rs.6000 and cost of glass increases
to Rs.2000.
By using heater our output will be approximately 9.5L Thus for 1 year the output is 3467L.
Let us assume 15Rs/L as the cost of water. Then Rs.52012.5 will be the actual cost to buy this much
amount of water which is received for just Rs.22000 by using our solar still with heater. So within 6
months we are getting our money back and the remaining is profit.
10. CONCLUSION AND FUTURE WORKS
• The main fabrication process in this desalination system are metal cutting, welding, glass
cutting, sealing, painting and drilling.
• 3 litre/day can easily be obtained with such a portable system.
• For basic still without insulation productivity was 150 ml and maximum temperature of water
inside was 52.80
C and when insulated productivity became 950 ml and temperature remain
same.
• For still with heater without insulation productivity was 320 ml and maximum temperature of
water inside was 54.40
C and when insulated productivity became 1300ml and temperature of
water inside became 610
C.
• For still with heater and vacuum pump with insulation productivity was 1370 ml and maximum
temperature of water inside was 600
C.
• From the experimental analysis it is clear that proper insulation raised the output considerably.
This is basically due to the fact that the heat losses were arrested.
• The use of heater for just 40 minutes that is 0.83kWhr a day, increased the productivity about
35% more than the basic.
• It was found from the experimental analysis that increasing the ambient temperature will
increase the productivity, which shows that the system performed more distillation at higher
ambient temperatures.
• It was observed that when the water depth increases, the productivity decreased. These results
show that the water mass (water depth) has an intense effect on the distillate output of the solar
still system.
• Vacuum pump increases the productivity by a very small amount only.
• The use of thicker glasses gave faster condensing rate thereby increasing the productivity.
• The desalination process is cost effective. The best method that we suggest is to preheat water
before providing it into basic solar still.

140
REFERENCES
[1] Anirudh Biswas, Ruby, Distillation of water by solar energy, vsrd-map, vol. 2 (5), 2012,
166-173.
[2] M.Koilraj Gnanadson, P.Senthilkumar, G.Sivaraman, Design and Performance Analysis of a
vacuum single basin solar still, International journal of advanced engineering technology
2011 (174-181).
[3] K. Sampathkumar, T.V. Arjunan, P. Pitchandi, P. Senthilkumar, Active solar distillation,
Renewable and Sustainable energy reviews 14 (2010)1503-1526.
[4] A.E. Kabeel, Performance of solar still with a wick concave evaporation surface, Twelfth
International water technology conference, iwtc12 2008 Alexandria, Egypt.
[5] Kaabi Abdennacer, Trad Rachid, Department of climatic engineering, university of mentouri,
25000 constantine, Algeria, Study of the optical performance of a solar still with a double
slope and a greenhouse effect.
[6] Hazim Mohameed Qiblawey, Fawzi Banat, Solar thermal desalination technologies,
desalination 220 (2008) 633–644.
[7] Prof.Nilamkumar SPatel, Prof.Reepen R Shah, Mr.Nisarg M Patel, Prof.J.K.Shah, Mr.Sharvil
B Bhatt, Effect of various parameters on different types of solar still: case study, International
journal of innovative research in science.
[8] Bilal A. Akash, Mousa S. Mohsen, Waleed Nayfeh, Experimental study of the basin type
solar still under local climate conditions, Energy conversion & management 41 (2000)
883-890.
[9] Ajeet Kumar Rai, Vivek Sachan and Bhawani Nandan, “Experimental Study of Evaporation
in a Tubular Solar Still”, International Journal of Mechanical Engineering & Technology
(IJMET), Volume 4, Issue 2, 2013, pp. 1 - 9, ISSN Print: 0976 – 6340, ISSN Online:
0976 – 6359.
[10] Ajeet Kumar Rai, Vivek Sachan and Maheep Kumar, “Experimental Investigation of a
Double Slope Solar Still with a Latent Heat Storage Medium”, International Journal of
Mechanical Engineering & Technology (IJMET), Volume 4, Issue 1, 2013, pp. 22 - 29,
ISSN Print: 0976 – 6340, ISSN Online: 0976 – 6359.
[11] Ihsan Mohammed Khudhur and Dr. Ajeet Kumar Rai, “Experimental Study of a Tubular
Solar Still Integrated with a Fan”, International Journal of Advanced Research in Engineering
& Technology (IJARET), Volume 5, Issue 3, 2014, pp. 1 - 8, ISSN Print: 0976-6480,
ISSN Online: 0976-6499.
[12] Hasan Falih M., Dr. Ajeet Kumar Rai, Vivek Sachan and Omar Mohammed I.,
“Experimental Study of Double Slope Solar Still with Energy Storage Medium”,
International Journal of Advanced Research in Engineering & Technology (IJARET),
Volume 5, Issue 3, 2014, pp. 147 - 154, ISSN Print: 0976-6480, ISSN Online: 0976-6499.

20120140505015

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