08-16-2017, 08:56 PM
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DESIGN FABRICATION AND ANALYSIS OF A BASIN TYPE SOLAR WATER STILL
Team: Ajo Thomas
Anil N Sahodaran
Neeraj Nair Padmakumar
Guide: Mr. Pradeepmon.T.G, lecturer, Mechanical department,
AIM OF THE PROJECT
The project aims at evolving a simple and economic
design for the basin type water still. Special attention is paid
towards its functional and economic viability. A thorough
analysis of the design has been carried out.
EVAPORATION
Evaporation is the slow vaporization of a liquid and the reverse of condensation. A type of phase transition, it is the process by which molecules in a liquid state (e.g. water) spontaneously become gaseous (e.g. water vapor). Generally, evaporation can be seen by the gradual disappearance of a liquid from a substance when exposed to a significant volume of gas.
FACTORS INFLUENCING THE RATE OF EVAPORATION:
Concentration of the substance evaporating in the air
Concentration of other substances in the air
Concentration of other substances in the liquid (impurities)
Flow rate of air
Inter-molecular forces
Pressure
Surface area
Temperature of the substance
AIM
To purify:
1. Brackish water
2. Sea water
3. Pond water, murky water from wells etc.
Ease of installation, maintenance and use.
Economy is an equally important criterion.
DESIGN OBJECTIVES FOR AN EFFICIENT SOLAR STILL
For high efficiency the solar still should maintain:
A high feed (undistilled) water temperature.
A large temperature difference between feed water and condensing surface.
Low vapour leakage.
HOW TO
A high feed water temperature can be achieved if:
A high proportion of incoming radiation is absorbed by the feed water as heat.
Heat losses are kept low
The water is shallow so there is not so much to heat.
A large temperature difference can be achieved if:
The condensing surface absorbs least radiation
Condensing water dissipates heat rapidly.
Material Selection
The entire apparatus is made of glass having a transmissivity of 70%.
Black limestone (Kadappa stone) as a heat absorber.
Coir as insulator.
Collectors: Two sheets of thin glass of 135cm x 75cm arranged symmetrically over the side walls like a roof act as the collectors cum condensing surfaces.
Aluminium fittings.
Special silicone-based glue is used for sticking glass.
SOLAR RADIATION ON TILTED SURFACES USING EMPIRICAL RELATIONS
The ratio of the radiation flux falling on a tilted surface to that falling on a horizontal surface is called the tilt factor ®
Tilt factors for each kind of the following radiations exist:
Beam Radiation
Diffuse Radiation
Reflected Radiation
MARKET RESEARCH
The market for the product includes whole of rural Indian population and some of the water scarce urban areas like Chennai.
This comprises around 70% of India s population; the exact number being 70 cores.
Assuming around 10 % of them will actually be interested in buying this product the demand for the product is 70 x 0.1 = 1.4 crore units.
This makes the market size to come up to around Rs 140 crore.