Dear Immanuel,

Theoretically, in order to increase the rate of evaporation in a solar still should increase the heat of the Sun. This can be done in two ways. First, by increasing the time the heating of the Sun. Second, by increasing the angle at which the sun's rays fall. The best angle of 90 degrees to the surface of the water. Technical details are not considered here.

Regards,

Milivoj B. Gavrilov

The most important factor that affects level of production of the solar still is the amount of solar radiation on the glass cover, called irradiance. Not all of the solar energy that contacts the glass will actually be used for evaporation of the water in the basin because it gets reflected and absorbed by anything it passes through. An energy flow diagram that shows that part of the sunlight is reflected and absorbed by the glass, the water, and the basin surface. If the still is not perfectly sealed and insulated there will be heat losses to the surroundings.

Dear Immanual,

check http://onlinelibrary.wiley.com/doi/10.1002/ep.12280/full

Additonally was is mentioned above it is possible o enhance the yield of solar still by increasing the surface area of water. As the area of stacked water increases, there is a greater possibility of an increase in temperature of the water and hence the evaporation rate from the top layer of basin water. 

http://www.sciencedirect.com/science/article/pii/S0196890415011838

it is observed that the yield of freshwater from the solar still with spherical ball salt storage achieves the maximum yield of 3.7 kg/m2 as compared to a conventional single slope solar still with sponge and without any storage material as 2.7 and 2.2 kg/m2 respectively. The deviations between theoretical and experimental values for with spherical ball salt storage, with sponge and conventional solar still are found as 16.1%, 9.7% and 4.0% respectively. Payback period of the present solar still is found as 4.3 months as it is quicker than other conventional single slope solar still.

best regards

Johannes

There are many augmentations to increase the yield of the solar still

There are many factors that increase the increase of yield solar still

Using wick materials in the still

Using internal/ external reflectors

Using thermal energy storage

Coupling solar still with mini solar pond

Coupling solar still with solar collectors

Using external condenser

when the surface of liquid media undergoing evaporation is covered with a thin, floating layer of discrete, imperforate particles of an inert solid material, the rate of vaporization of volatile liquids in the liquid media is effectively increased at-a given temperature over the rate of vaporization in the absence of floating layer.

Please refer : 

 P.Patel and others    "A review to increase the performance of solar still.....multi layer absorber ".  Int. J. On recent and innovations trend in computing and communication volume 2 issue 2. ISSN 2321-8169.

Increase the surface area and reduce thickness of water filim

it is more efficient by having water droplets instead of water film in basin.

If the droplet radius is small it increases the evaporation rate this is for cooling tower this also applicable for solar still

Hi,

Have anyone done a solar still simulation before?

Regards,

Ahmed

http://www.ijritcc.org/download/A%20Review%20to%20Increase%20the%20Performance%20of%20Solar%20Still%20Make%20It%20Multi%20Layer%20Absorber.pdf

Multiple-effect distillation

Good discussion.

Using reflectors

The factors affecting the evaporation rate is the incident solar radiation as the solar radiation increases the temperature of the water in the still increases. It is found also that the solar radiation collection efficiency under the water still layer affects also the evaporation rate so that the evaporation rate increases as the the collection deficiency increases. The last factor is the thickness of the water layer.

For more information about the factors affecting the distilled water productivity from single slope water still is given in the the paper at the link: Article Experimental Evaluation of a Single Slope Solar Still

Best wishes

I agree@ Abdelhalim Zekry

reduce the distance between the surface of the evaporation and the conical glass

NEW PORTABLE SEAWATER DESALINATION SOLAR PLANT BASED ON MEMBRANE DISTILLATION TECHNOLOGY

Make the modification in absorber plate or basin surface area.

The rate of evaporation can only be increased if the saturated layer of vapor above the surface is blown away. This is not possible by increasing the radiation intensity but only by wind.