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Table 2 Design parameters of a passive solar still

From: A review of optimum parameter values of a passive solar still and a design for southern Bangladesh

Parameters

Significance in output/yield

Optimum value

Ref.

No. of slopes

Single slope has a higher yield than double slope

Single slope

Garg and Mann (1976)

No. of Basins

Double basin gives higher yield than single basin stills

Single basin in the context of easy making of the still

Mahdi (1992)

Inclination of glass cover

Angle of inclination has to be equal to the latitude to get maximum normal solar radiation

23.5\(^\circ\) for Dhaka

Singh and Tiwari (2004)

Glass cover thickness

Lowering glass cover thickness increases the temperature difference between water and inner glass cover

3- to 4-mm glass cover thickness

Ghoneyem and Ileri (1997)

Gap distance between water and glass cover

Decreasing the gap distance between the glass cover and water surface can improve yield up to 11%

8-cm gap distance can be used

Ghoneyem and Ileri (1997)

Stepped solar still

To lower gap distance between glass cover and water surface stepped solar still can be used

Water depth of 4–5 mm and 100–120 mm tray width is used

Velmurugan et al. (2008)

Energy absorption and storing materials

Charcoal or fins of aluminum covered with cotton cloth. Small (20–30mm) black stones or gravels can be used as energy storage medium

Charcoal and small black stones can be used

Abdallah et al. (2009), Cooper (1972)

Insulation thickness

Insulation thickness has to be maximum so that no heat loss can occur but we have to consider the cost as well

0.9- to 0.13-m insulation thickness

Garg and Mann (1976), Al-Karaghouli and Alnaser (2004), Al-Hinai et al. (2002)

External and internal reflector

External and internal reflectors both increase distillate productivity

Internal reflectors can be added with side walls and external reflectors at the back side of the still

Tanaka and Nakatake (2006), Tanaka (2009, 2011)

Sun tracking system

Sun tracking can improve the efficiency of the still but because of movable parts and other electrical circuitry requirement it is not that much cost-effective

Sun tracking can be avoided to maintain the cost-effectiveness

Kalogirou (1996), Abdallah and Badran (2008)

Wick material

Black cotton cloth or charcoal particle is the best wick for passive solar still

Light black cotton cloth can be used

Minasian and Al-Karaghouli (1995), Murugavel and Srithar (2011)

Condenser

Condenser always increases the yield in solar still

A passive condenser should be added

Fath and Elsherbiny (1993)