Devices & Sensors
Title of Process/ Know-how/ Product/Design/Equipment
Improved solar still
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:
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
