03-03-2010, 06:17 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.
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.