Solar Desalination

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Solar Desalination

• Herb Stumph
• Renewable Energy Systems
• April 26, 2000

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Even More Motivation ...

• 80 of fresh water is frozen
• 1.3 billion people worldwide have no access to
  clean supplies of water
• John Hopkins report projects that that number
  will increase to 2.8 billion people by the year
  2025
• DOE Report states the 70 of India's surface
  water is polluted

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Why use solar to desalt?

• Good from a Second Law Perspective
• Regions that are short on water have plenty of
  sun
• Clean, No combustion wastes, chemicals
• Prevents the use of fossil fuels
• Not only solar, wind and geothermal applications
  exist.

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Methods
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Modeling Active SolarDistillation

• Kumar proposed for Delhi
• Small-scale, personal use

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The Model

• Write Energy Balances
• Water mass
• Glass cover
• Basin liner
• Solve for the temperature of the glass and water
• Use them to find the fresh water yield

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Results

• Ran Simulation using system parameters that Kumar
  et al. used
• Results within 20
• Tucson vs. Delhi
• clear days in the summer
• adjusting for that 5

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ResultsBasin Depth
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Optimum Collector Angle

• 45 deg. coll.
• 0.03 m deep
• 10 deg. still
• 761 gal/m2 yr

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Economics

• Assumed same system to desalinate the water just
  different heat sources.
• Compared the price of adding the same amount of
  electrical resistance heat to the system to the
  capital cost of the system.
• The system pays for itself in 2.2 years.

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Recommendations

• Add cooling to the glass cover
• Vary the area of basin and collector