Household solar still with easy operation and maintenance and enhanced output

Patent metadata

Field	Value
Publication number	US-9908790-B2
Application number	US-201314382534-A
Country	US
Kind code	B2
Filing date	Mar 4, 2013
Priority date	Mar 2, 2012
Publication date	Mar 6, 2018
Grant date	Mar 6, 2018

Abstract

The invention discloses the design of an improved household solar still with enhanced output and high recovery. The output and recovery are enhanced by (i) aligning the top glass and basin so as to maximize the input solar radiation, (ii) using North-South reflectors in V trough configuration to further raise the incident radiation, (iii) employing metallic condensers on sides to maximize condensation efficiency, (iv) using suitably heated and cooled saline water by taking advantage of ambient temperature differential during a day and using such water as feed water and condenser water respectively. Use of detachable top glass assembly and teflon cork at the bottom allows for easy cleaning of the interior of the still and discharge of concentrate, respectively. The still is also demonstrated to be useful for other applications where, besides producing distilled water, the concentrate is a more value added product than the feed.

First claim

We claim:

1. A household solar still for desalination of brackish water comprising:
a frame;
a tilted water basin having five partitions for holding water in a tilted position;
a tilted top glass assembly positioned over the tilted water basin, the tilted water basin and the tilted top glass assembly being tilted at an angle in the range of 18.9 to 20° to the horizontal with a top portion of the tilted top glass assembly pointing northwards and a bottom portion of the tilted top glass assembly pointing southwards, the tilted top glass assembly being fixed to the frame;
a pair of a top reflector and a bottom reflector, the top reflector being fixed to a top edge of the solar still and the bottom reflector being fixed to a bottom edge of the solar still, each of the reflectors being in the form of anodized aluminium sheets, attached to a polymeric sheet;
a first and a second metallic condenser being attached on eastward and westward sides of the solar still, the first metallic condenser being covered by a first tray, and the second metallic condenser being covered by a second tray;
a third metallic condenser being attached to a back side of the solar still, the third metallic condenser being positioned so as to be substantially covered by the shadow of the reflector;
each of the first and second metallic condensers comprise a lower steam chest part and an upper part;
the lower steam chest part comprises a steam inlet and a condensed water outlet; and
the upper part comprises a cold water inlet, a hot water outlet and a water holding/flow portion located between the cold water inlet and the hot water outlet, wherein the upper part is adapted to receive brackish water and to allow flow to the brackish water under gravity at a specified flow rate over the lower steam chest part to facilitate condensing of steam on an inner top surface of the lower steam chest part.

2. The solar still as claimed in claim 1 , wherein the pair of the top and the bottom reflectors form a V-trough configuration and the angles of the two reflectors with respect to the vertical plane are optimized using geometric formula according to the position of the sun to have maximum solar energy on the tilted top glass assembly helping in maximizing evaporation.

3. The solar still as claimed in claim 1 , wherein for a square meter of top glass assembly area, a tilted water basin volume is 18 L.

4. The solar still as claimed in claim 1 , wherein the first, second and third metallic condensers are corrosion resistant.

5. The solar still as claimed in claim 1 , wherein the first, second and third metallic condensers further comprise a sump and an insulated tank with a removable cover positioned behind the solar still, that cools the brackish water through night sky radiation to produce a cooled brackish water and the cooled brackish water flows over the first, second and third metallic condensers by gravity at an optimum rate and collects in the sump.

6. The solar still as claimed in claim 1 , wherein the tilted top glass assembly is designed to be detachable to enable cleaning of a solar still interior and discarding of the concentrate every day prior to feeding of fresh stock of brackish water through leakproof plugs attached to a lower part of the tilted water basin.

7. The solar still as claimed in claim 1 comprising brackish water and an edible dye added to the brackish water.

Assignees

• Council Scient Ind Res

Inventors

• Maiti Subarna
• Patel Pankaj Arvindbhai
• Bhatt Chitrangi Bankimbhai
• Bharadia Jitendra Narsinhbhai
• Gajjar Mahesh Ramjibhai
• Bapat Pratap Sashikant
• Ghosh Pushpito Kumar

Classifications

• F24J2/16

  Mechanical Engineering · mapped topic

• F24J2/523

  Mechanical Engineering · mapped topic

• B01D1/0035

  Solar energy (for treatment of water C02F1/14) · CPC title

• C02F2103/08

  Seawater, e.g. for desalination · CPC title

• B01D1/0082

  Regulation; Control · CPC title