| Title of Process/ Know-how/ Product/Design/Equipment

Improved solar still

IPR Status & Details:

US 9908790B2

Application/Uses/Problem being addressed

  • Scarcity of potable water for drinking and cooking is a challenge confronting people in remote locations like coastal areas and small islands.
  • Seawater desalination through techniques such as RO and ED are costly propositions, difficult to scale down to individual household levels, and grid power is unreliable in many locations.
  • Many of these locations are blessed with abundant sunshine
  • There is merit in low-tech solutions such as desalination in a solar still, a device that enables evaporation and subsequent condensation of water in an enclosed unit assisted by solar thermal radiation.
  • Salient Technical Features including Competing Features/ Impact

  • Maximum output of 5.0 litres/m2/day.
  • Incorporate reflectors in V-trough alignment along the North-South edges of the still, which is the simplest of concentrating technologies to enhance solar intensity on collector
  • Incorporating steps or partitions in the basin. The steps (i) allowed the water to be held in the tilted position, thus maximizing the absorption of solar beam radiation by the suitably tilted absorber surface, (ii) triangular exposure area, avoiding shadow effect as generally reported in literature for stepped solar stills, (iii) reduction in the free space thereby maximizing the partial pressure of water vapour and (iv) enhanced the contact area between water and heated basin surface.
  • TRL Level & Scale of Development:- TRL 5 TRL Reference

    -

    Business scope & opportunity (in terms of scale, cost, market etc.)

    Predominantly societal application. Proliferation anticipated through licensee.

    Environmental Considerations

    Clean and green technology

    Status of Licensing:

    Ready for licensing

    Status of Commercialization:

    Not yet licensed

    Major Raw Materials Needed

    Hardware material like metallic sheets, anodized aluminium sheet, rods, pipes etc.

    Saline water of any TDS can be used as feedwater

    Major Plant Equipment and Machinery Required

    Modular units are needed to be fabricated in workshop

    Techno-Economics

    Considering a 3m2 solar still unit

    Water output (average): 12 LPD

    300 days in year and 5-year service life: 18000 L

    Cost of water/L: ₹4.5/L

    Bottling cost: ₹3/L S

    elling price: ₹15/L

    Profit: ₹7.5/L

    Profit/year: ₹27000

    Payback: ~3 years

    Technology Package

    Available on request

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