Engineering

Solar still

Materials science

Thermal conductivity

Biochemistry

Mechanical engineering

Physics

Membrane

Glazing

Desalination

Graphite

Optics

Thermal

Environmental science

Composite material

Chemistry

Meteorology

Cover (algebra)

Pyramid (geometry)

Engineering physics

Renewable Energy

This study aims to enhance the performance of pyramid-shaped solar stills using a high thermal conductivity absorber plate (graphite) and cooling the glass cover. To achieve this aim experimentally, the absorbent surface manufacture from a graphite material with a thickness of 25 mm. The graphite is characterized by the high thermal conductivity, as well as, the graphite represents a sensible store medium where the thermal energy is stored during the period of the high value of solar radiation and is reclaimed back into the basin water during the period of lower solar radiation intensity and after sunset. Also, the outside surface of the glass cover is cooled to increase the rate of water vapor condensation and then improve the distillate water production. A traditional pyramid-shaped still and a pyramid-shaped still using a high thermal conductivity absorber plate and cooling the glass cover (modified pyramid-shaped still) have been constructed and tested in Tanta University-Egypt, to get the effect of using graphite as an absorber surface and cooling the glass cover on the performance of pyramid-shaped still. The experimental results show that daily production of both modified pyramid-shaped still and a traditional pyramid-shaped still ranges from 9 to 9.19 and 4.37–4.43 l/m2day, respectively at the same ambient conditions. The improvement in the daily production of the modified pyramid-shaped still ranges between 105.9 and 107.7% as compared to a traditional pyramid-shaped still. Also, use the graphite with cooling the glass cover improves the everyday efficiency of the modified pyramid-shaped still by 97.2–98.9% as compared to a traditional pyramid-shaped still. The economic analysis presented that use the graphite and cooling the glass cover reduce the cost of distillate water produced from the pyramid-shaped solar still by 13.6%.

Enhancement of pyramid-shaped solar stills performance using a high thermal conductivity absorber plate and cooling the glass cover