UNIVERSITY followed by nausea, headaches, muscle cramps and


                                 

UNIVERSITY
OF NAIROBI

KENYA
SCIENCE CAMPUS

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DEPARTMENT
OF PHYSICS  

 

A
project Report on Generating Water for Survival in The Desert

Submitted
towards fulfillment of bachelor of education science

NAME:
KORIR HILLARY CHERUIYOT

REG.
NO: E37/4044/2014

SUBMITTED
ON:

Declaration
page

I hereby
declare that this project research is my own work and has not been submitted
for research at any other university.

Name:
Korir Hillary Cheruiyot.

Reg. no:
E37/4044/2014.

Signature:
__________.

Date:
______________.

This
project research has been submitted with my approval as the supervisor:

Name:
Dr. Sebastian M. Waita. (PhD), 
Department of Physics Coordinator, University of Nairobi.

Signature:
____________.

Date: ________________.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

ABSTRACT

This
project research involves a summary of work aimed at generating water for
survival in the semi-arid areas. The research is aimed at addressing challenges
faced by soldiers and people who tour desert places and in the long run their
stored water run out. Many of them may become weak as a result of dehydration,
hence may distract them from concentration on their work and may end up dying.
This can be solved by using the locally available materials to generate water
through solar still to sustain them for some time. This project may be
developed to bring a more lasting solution to the problem faced by people
touring or working in semi-arid areas.

Even
healthy water sources can contain harmful bacteria that can cause humans to be
ill and loose more body fluids. Dehydration strikes quickly and overcome the
minds irrationality and at the same time the volume of the blood in the body
reduces drastically. Because of inadequate supply of blood in the blood vessels
they then start to shrink followed by nausea, headaches,
muscle cramps and dizziness quickly follow. Emergency techniques are then required to safe the
situation, this emergency technique is solar still which is the readily
available. Solar still is also known as underground still or below ground
still.

It has
been proven scientifically that human beings can stay without water for at
least 3 days; this is possible if the temperatures moderate. It has also been
proven reduction of water in the level of water in the body reduces normal
bodily performance and also the mental performance. This therefore reduces the
ability of the person to be able to overcome the extreme temperatures and
conditions hence may not achieve their goal.

Underground
still uses the principle of greenhouse effect. In this process the sunlight
heat passes through the clear plastic paper that hits the humid soil. The water
then evaporates in form of vapor, hits the polythene barrier and condenses
below it then drops to the collecting jar. This water is purified and almost
90% clean hence can be fit for drinking if no other water is available.

 

 

 

 

 

 

 

 

 

 

 

 

 

TABLE OF CONTENTS

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

LIST OF FIGURES

1.     
Figure
1: Sketch of underground still

2.     
Figure
2:

3.     
Figure
3:

4.     
Figure
4:

LIST OF ABBREVIATIONS AND SYMBOLS

1. l-
Liters.

2. m-
Meters.

3. cm-
Centimeters.

4. m2-
Square meters.

5. Kw –
Kilo Watt.

6. Km –kilometer.

7. K –
Kelvin.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

CHAPTER ONE: INTRODUCTION

Solar
still is a simple way of distilling water using the heat from the sun which then
drives water through evaporation from humid. Solar stills are in two ways; pit
still or underground stills and box stills. We are going to focus on
underground stills. Impure water is present and in the humid soils which are
outside the container. The water from the humid soil is evaporated by radiant
heat from the sunlight passing through the transparent polythene bag.

Solar
still replaces the way nature makes rain. The sunlight heats the water to a
point of evaporation, the water evaporates in form of water vapor, then
condense on the polythene bag and drop to the at the weighted center to the
container collecting. This process removes impurities in such as heavy metals,
micro-organisms and even salts. This makes the water pure even more then rain
water.

Places
with greener grass or plants downstream is rich with moisture since the more
the greener the young plants are, the more they consume water and hence the
less green they are, little they use water. The ground that supports these
plants is very rich in moisture hence giving another best place to construct an
underground still.

These
places rich in moisture can be found easily without using more technical ways
but just nature. One of the ways of finding these places is by just looking
around these places which are mostly found downstream or valleys or down the
mountains. These places are the best since most plants are found there than
higher places which mostly contain rocks and loose sand.

Another
way these places could be determined is by following animals, birds and insects
that are found in the desert. Animals that mostly run down the valley go to
where the water is or where they have been, if there is no water then moisture
in the soil could be present. This is same to the case of the birds. There is
an interesting idea about the insects which are mostly bees they travel in
straight line from the beehive to where water could be found.

This
people who visit semi-arid places carry with themselves water to be used,
however, it may be impossible to carry water for many days, and survival
situations may create an unforeseen demand for water. If they are travelling
for 2 weeks, each person will require 25 L of water for drinking only which is
multiplied by the number of people to travel. Since the body requires at least 1L
of water each day, if this demand is not met, dehydration will result, leading
to heat exhaustion, heatstroke and death will occur within some days.

This can
be solved using simple materials that are cheap, portable and easily found. The
aim of this research is to generate water for survival that can be done to
enable the people to look for more reliable water sources.

 

 

 

 

 

 

CHAPTER TWO: LITERATURE REVIEW

Syria is
one of the countries in the world within arid areas. They use solar stills to
generate water or purify the available solar saline water. Syria has high solar
isolation. Hence one of the cheapest ways to have the water fit for drinking is
by solar still. In implementing use of solar still Syria in November 2010
designed, manufactured and piloted three similar solar stills for a day and it
was found that the stills produced water that were fit for drinking. It
condensed and purified the saline humid soil. (J.Lindblom, Renewable Energy
Systems, Lulea University of Technology, Lulea 2010)

Therefore;
since plants and many animals survive in desert then there is a possibility
that human beings who visit desert places can survive too. Since animals and
plants need water for them to live, then there is plenty of water in the desert
and people ought not to die because of dehydration in the desert. Innovative
ways need to be put in place so that they can help anyone stuck in the desert
get water.

Dehydration
sets in quickly in the arid areas due to intense scorching sun. This is due to
rampant loss if excretion from bodies of human beings. If one is found in such
situation in the desert, the simplest way of getting water is by condensation
of water vapor. The available sources where water can be condensed are dry
river beds. (WikiHow)

There are
some factors that affect the performance of solar stills, some of them are;
intensity of solar, water-transparent polythene bag, temperature differences,
ambient temperature, among others. The modes of heat transfer in involved in
solar still include; radiation which comes from sun and requires no medium of
transfer, this hits the humid soil. The water in the humid soil reaches the
temperature of evaporation and evaporates immediately.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

CHAPTER THREE: THEORETICAL
BACKGROUND

 The efficiency of the solar heat on one solar
pit approaches 60% all day. This is at its optimum at noon. The intensity of
the sunlight energy is utilized in vaporization of water. Solar still works on
two processes; the first process is evaporation, once the still is ready it is
allowed to stay in the sun, and then it absorbs short wave radiations energy.
Water in the still gets heated, as the temperature of the water increases
liquid water is converted to gaseous form which then evaporate towards the
transparent plastic paper leaving solid residue behind. This is followed by
condensation process, where the evaporated water hits the plastic paper and
slowly condenses on the paper forming droplets of clean water. This water then
rolls down to toward the weighted center where they drop to the collecting
container.

The water
produced is clean since no impurity can turn into gaseous state and evaporate.
This natural water purification has PH level balanced.

1.      Sunlight radiations.

2.      Support stick.

3.      Water droplets.

4.      Evaporating water.

5.      Collecting container.

6.      Collected water.

7.      Supporting stone.

8.      Transparent polythene bag.

Figure 1-A
sketch of underground still

 

Just like other stars the sun is
composed atoms and nuclei occupying approximately 94%, helium covering 5.9% and
other elements take 0.1%. The sun is in gaseous form having a mass of about
2X1030 kg and radius of about 7X105 km. When compared to
the earth’s radius of approximately 3.3X105 km the sun’s radius is
higher. The sun produces energy at a rate of 3.8X1023 Kw. With the
sun being approximately 1.5X108 km from the sun it taps a fraction
of the energy produced.

Through fusion furnace most of this
energy is produced then transferred radially outwards through solar energy
which radiates at a temperature of approximately 5800 K. Electromagnetic
radiations emitted from the sun are converted to other forms of energy. The
radiations reach the earth either directly or by reflection. Short wave
radiations are reflected back to the space but those absorbed are re-radiated.

Some sunlight radiated from the sun
pass through the atmosphere while others are absorbed by clouds, pollutants
from power plants among others. The particles on the atmosphere reduce 10% of
the radiations. When it is cloudy the reduction can go up to 100%.

Still is used to draw water from
soil and from plants. When constructing the belowground still a place with
sufficient moisture ground is required, these places in desert places could be
dried river beds, oasis, or dried places which formerly contain water. These
places have some sand or soils that contain moisture. These are the best places
in which underground still can do since it’s an open ground having sufficient
sunlight heat.

Condensations of water in solar
stills by themselves are used as supplement water source and thus may not be a
reliable water source. They should not be relied on to provide daily water used
in daily activities such as bathing, washing among others. The still measuring
40 cm wide and 30 cm deep produce 100 ml up to 150 ml of water per day.

These site
needs to be in an open ground where sunlight is readily available. Sunlight is
the second most important commodity after moisture. Sunlight is needed to
evaporate the moisture. The sunlight needs to be as scorching as possible to be
able to evaporate the moisture from the soil and also the plants to be able to
transpire. The experiment need not to be in a shade or in place without
sufficient sunlight.

The next
step is to start the process of condensing the water that is available. The
ground with moisture is the primary source of water, and the secondary sources
of moisture are leaves from the plants. When the sun heat hits the wet soil and
green plants water will evaporate. The evaporated water gets trapped on the
lower part of the transparent paper. They are condensed here since the vapors
encounters the paper which is cooler that the temperatures inside the hole.

They form droplets
which collect towards the center where a stone has been placed at the center of
the paper. This stone helps to bring the condensed water together as thy drop
into the collecting jar. The transparent paper has been fully covered by the
edges so that no air is able to escape.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

CHAPTER FOUR: MATERIALS AND RESEARCH
METHODOLOGY

                 MATERIALS

The following materials were used to construct
an underground solar still:

·        
1L Container.

·        
1 m2   transparent
polythene paper.

·        
A Spade.

·        
Pieces of 4-inch sticks.

·        
100ml graduated cylinder.

 

RESEARCH METHODOLOGY

Finding water for survival by condensation in
the desert is one amongst ways of getting water in the desert. The research was
carried out in an open place with a lot of sunlight in two ways and the following
procedure was followed:

Method
1

·        
A round still with a diameter of 60 cm wide
and 50 cm deep was dug and soil was removed and placed outside close to the
hole.

·        
The 1L container was placed at the center of
the hole.

·        
The hole was then covered with the transparent
polythene bag. Then the 4-inch sticks were pierced through the transparent
polythene at an interval of 10cm all-round the hole. Soil was then used to
cover the remaining spaces left by the sticks so that no evaporating moisture
escaped from the hole.

·        
A smooth stone was then placed at the center
of the polythene bag from the outside so that it hangs and forms an inverted
cone over the container.

·        
The project was left on the field for 48 hours
on hot sunny days.

Method
2

·        
A round hole with a diameter of 60 cm wide and
50m was dug and soil was removed and placed closed to the hole.

·        
The 1L container was placed at the center of
the hole and around it was green leaves with some young plants uprooted from
the surrounding.

·        
The hole was then covered with the transparent
polythene bag. Then the 4-inch sticks were pierced through the transparent
polythene at an interval of 10cm all-round the hole. Soil was the used to cover
the remaining spaces left by the sticks so that no evaporating moisture escaped
from the hole.

·        
A smooth stone was then placed at the center
of the polythene bag from the outside so that it hangs and forms an inverted
cone over the container.

·        
The project was left on the field for 48 hours
on hot sunny days.

 

 

CHAPTER FIVE: RESULTS AND DISCUSSION

RESULTS

After covering the hole for 10 minutes, the
transparent polythene bag had traces of some white substance from the bottom.
And the transparent paper was no more transparent.

After 1 hour of experiment some lines formed
on the lower part the leads to the center of the paper where a weight had been
placed. Water droplets could be seen on the transparent paper.

All along from the 1st hour of experiment to
the 48th hour of the experiment water droplets formed and the more
water droplets formed the more the lines headed to the center stone.

After the elapse of the 48 hours, the volumes
of water that had been collected were measured.

It was found that the experiment without the
leaves produced 200 ml while the one having the green leaves produced 230 ml of
water.

At the end of the 48 hours the leaves that had
been placed inside the hole turned brown in color and the soil inside the hole
were dry. This is an indication that water had been drawn from both the soil
and the green plants.

DISCUSSION

The white substance that formed below the
polythene was water vapors that had evaporated from the walls of the hole and
the green plants. They are in form of water droplets but their size is too
small. They were the first to encounter sunlight heat.

After the 1 hour the exposure to sunlight is more
intense and more evaporation takes place.

The upper part of the polythene is cooler than
the bottom. So, it acts as sheet to cool the water vapors. This is why they
drop after getting to the paper.

The experiment without leaves were able to
record a slightly lower volume that the part having the leaves. This was
because the leaves were able to produce 30ml of water. Leaves were added so
that they increase the surface area over which the water can be drawn from.

Nevertheless, the volume of water collected
without the green plants is sufficient given that the there are many of such
holes.

The water droplets collect themselves below
the cone shaped plastic paper and then flow downwards to the tip of the cone
shaped paper where they drop to the collecting container.

 

 

 

 

 

 

CHAPTER
SIX: CONCLUSIONS AND RECOMMENDATIONS

CONCLUSIONS

One can drink the collected water by use of
straw that run through the surface but without disturbing the project. The
straw runs up to the bottom of the collecting container. The other way can be
waiting until the end and then collect all as you empty them into bigger water
storage.

Underground solar still is one of the ways
that have been used to purify water for safe drinking. As water evaporates from
the humid soil and transpire from the leaves. It leaves behind salts, heavy
metals and micro- organisms. This brings up water that is safe for drinking. However,
this water is in small volume that may not sustain an average family. It’s able
to sustain travelers who have no other source of water.

Many underground stills have to be dug in
order to increase the volume of water that is being collected. Since a single
hole provide an average of up to 220 ml of water maximum when the soil is very
humid. This volume may reduce to 200 ml minimum if the soil is less humid or
low sunlight energy. Distillation by solar does not kill some harmful chemicals
and some bacteria because the water is not heated up to boiling point.

The underground still requires very little
maintenance, it is also portable.

RECOMMENDATIONS

The water obtained in an underground still
maybe of low volume, but the more the stills the more the volume of water
collected is increased. This project is the best suited when the sunlight heat
is hottest. The transparent paper should not have holes on its surface. If
present then water vapor may escape through them.

REFERENCE

1. ErVinayChauhan/solar-still-project-report.

2. FM21-76_SurvivalManual.pdf.

3. hawale3/solar-still-32904283.

4. desertUSA.comss

 

 

 

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