Distillation is one of many processes that can be used for water purification. This requires an energy input as heat, electricity and solar radiation can be the source of energy. When Solar energy is used for this purpose, it is known as Solar water Distillation. Solar Distillation is an attractive process to produce portable water using free of cost solar energy. This energy is used directly for evaporating water inside a device usually termed a “Solar Still”. Solar stills are used in cases where rain, piped, or well water is impractical, such as in remote homes or during power outages. Different versions of a still are used to desalinate seawater, in desert survival kits and for home water Purification. For people concerned about the quality of their municipally-supplied drinking water and unhappy with other methods of additional purification available to them, solar distillation of tap water or brackish groundwater can be a pleasant, energy efficient option. Solar Distillation is an attractive alternative because of its simple technology, non-requirement of highly skilled labour for maintenance work and low energy consumption.
The use of solar thermal energy in seawater desalination applications has so far been restricted to small-scale systems in rural areas. The reason for this has mainly been explained by the relatively low productivity rate compared to the high capital cost. However, the coming shortage in fossil fuel supply and the growing need for fresh water in order to support increasing water and irrigation needs, have motivated further development of water desalination and purification by renewable energies.
1. Under the guidance of
Santhosh K.G
Assistant professor
Mechanical engineering
M.I.T Mysore
A Technical Seminar on
WATER PURIFICATION USING
SOLAR STILL
Submitted by
Mohamed Shakeeb Ahmed
4MH11ME069
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2. INTRODUCTION
• A solar still is a simple way
of distilling water.
• It uses solar energy to distill the water.
• It removes impurities such as salt and
other microbiological organisms.
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5. Benefits of Distillation
• It produces water of high quality.
• Maintenance is almost negligible.
• Any type of water can be purified into potable water
by means of this process.
• Wastage of water will be minimum.
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6. Types of solar still
• Spherical solar still.
• Hemispherical solar still.
• Pyramid solar still.
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11. Concept for making a good solar
still
• The cover can be either glass or plastic.
• Glass is preferable to plastic because most plastic
degrades in the long term due to ultra violet light
from sunlight.
• The use of the mirror reflector will increase the
temperature of the solar still basin.
• Sufficient Insulations of wool, thermocol, sealants
etc. must be provided inside the basin in order to
prevent loss of heat.
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12. Estimation of water output
Estimate: 3.91 liters/𝒎 𝟐
/day
Q=
𝑨.𝑬.𝑮
𝟐.𝟑
A = Aperture area of the still in 𝒎 𝟐
E = Efficiency of the still usually taken as 50%
G = Global radiation energy in MJ/𝒎 𝟐(Approx. 18 MJ/𝒎 𝟐)
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13. Advantages
• Free of charge sun energy (during sunlight it
eliminates 500 Watt electric consumption per one
hour of sunlight).
• There are no moving parts; it is therefore reliable and
almost maintenance free (cleaning is required
though).
• Water taste is claimed to be better since the device
act as a Solar Water Vaporizer and it doesn’t boil the
water (resembling rain water).
• Neutral pH is claimed (like rainwater), not like the
not neutral pH of steamed distilled water.
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14. Disadvantages
• Low distillate output per unit area.
• Leakage of vapour through joints.
• High maintenance.
• Productivity decreases with time for a variety of
reasons.
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17. Conclusion
• It was found from the experimental analysis that
increasing the ambient temperature from 32°C to
47°C will increase the productivity by approximate
12 to 23%.
• It was observed that when the water depth increases
from 0.01m to 0.03m the productivity decreased by
5%.
• Solar still productivity can also increase by use of
reflector by 3%.
• Capital cost can be reduced by using different designs
and new materials for construction of solar stills. 17
