How solar water distillation works- Advantages and Disadvantages.

1. RANCHI WOMEN’S COLLAGE, RANCHI
Solar Water Distillation
Presented By:- Nelu Bharti
Roll:- 16mscho30
Subject:- Chemistry

2. Introduction
Cleandrinking water is the basic necessity for every
human being, but about 1.1 billion people in the world
lacked proper drinking water.

3. Water purification
There are many different types of water purification processes
such as filtration, reverse osmosis, ultraviolet radiation, carbon
absorption, but the most reliable processes are distillation and
boiling .

4. Boiling and distillation
Boiling is used asamethod of water purification. Boiling is
commonly advocated asan emergency water treatment method,
or asamethod of portable water purification in rural or
wilderness settings without accessto apotable water
infrastructure.
Water purification, suchasdistillation, is especially important in
regions where water resources or tap water is not suitable for
ingesting without boiling or chemicaltreatment.

5. Solar water purification
In solar distillation water is evaporated; using the energy ofthe
sun then the vapor condensesaspure water. Thisprocess
removes salts and other impurities.
Solar energy is allowed into the collector to heat the water. The
water evaporates only to condenseon the underside of the
glass.When water evaporates, only the water vapor rises,
leaving contaminants behind. Thegentle slope of the glass
directs the condensate to acollection trough, which in turn
delivers the water tothe collection bottle.

6. Theory
Energy from the sun per square meter per day =1000 Watt (1300 Wattaccurately)
=1000 x3600 joules perhour
=3600 kilojoules per hour
Heat of vaporization ofwater
Specific heat of water
=2257 kilojoules perkg
=4.19 kilojoules per kgper Kelvin
Factors effecting evaporation
Concentration of vapor inair
Surface area of water
Pressure of vessel
Temperature of water
Boiling point of water at sealevel 100 degree C.
Boiling point of water may be decreased by decreasing thepressure.
-pressure may be decreased by going "above sealevel".
-pressure may be decreased by "applying alow pressure"
Relatively cooler surface for condensation.
High vapor pressure
Low temperature

7. Application
 Industries for industrial processes
 Hospitals and Dispensaries for sterilization
 Garages and Automobile
Workshops for radiator and battery maintenance
 Telephone Exchange for battery maintenance
 Laboratory Use for analytic work
 Marshy and costal area To get fresh potable water

8. Advantages
 Produces pure water
 No prime movers required
 No conventional energy required
 No skilled operator required
 Local manufacturing/repairing
 Low investment
 Can purify highly saline water (even sea water)

9. Disadvantages
 Solar distillers don’t kill bacteria and they don’t break down
harmful chemicals because they don’t boil the water.
 The large area tilted glass cover might be an attraction to bugs
and insects.
 Low production capacity, not enough for the drinking water
needs of the average family.
 It is weather dependent process.
 Its use a lot of space.
 It is cost effective.

10. Design Overview
 Highly insulated
no heat loss
 Mirrors to reflect radiation
 Small bodies of water
 Self regulating water level
 Easy cleanup / collection

11. Conclusion
1.We want to remove physical contaminants.
2.Target users are poor countries where clean water is
unavailable.
3.Designing a scalable purification system of physical and
ultraviolet stages.
4.Keep cost and maintenance low so that it can be applied
to our target users.

12. Future Scope
In past few years, development of various desalination technologies in India
is really appreciable. Chennai has two desalination plants based on RO
process. RO process may be a reliable technique to supply fresh water, but it
is far from being the most sustainable solution because of high rejection
rate. Alternatives such as use of solar energy can be a better solution as it is
sustainable in nature. India, being a tropical country, is blessed with plenty of
sun shine. The average daily solar radiation varies between 4 and 7 kWh per
square meter for different part of the country. There are on an average 300
clear sunny days a year. Thus, it receives about 5000 trillion kWh of solar
energy in a year. The highest annual global radiation is received in Rajasthan
and northern Gujarat which promises huge potential for solar desalination
plant in these areas.

13. Available Products