Assessment of solar distillers with cement layer and cement cylinder fins as low-cost and locally available thermal storage materials

ABSTRACT

Most regions of the world, including the Algerian desert (southeast of Algeria, the El-Oued region in particular) suffer from pure water scarcity, although there is a huge stockpile of groundwater, it is salty water. Solar stills are one of the best solutions to the problem of freshwater shortages because it depend on solar energy, which is abundant throughout the year in southeastern Algeria. Due to the low productivity of solar stills, the current experimental study aims to create simple and inexpensive solutions to improve the productivity of solar stills. This was done by manufacturing the absorption basin from a concrete layer, with the addition of cement cylindrical fins and which were used as energy storage materials in addition to the use of cylindrical fins helped to increase the heat transfer area between the absorption surface (thermal storage materials) and basin water. To achieve this goal, two single-slope solar distillers were built and tested in this article, the first is Single Slope Solar Distiller with a Cement Layer (2 cm) placed as absorbent at the bottom base of the basin (SSSD-CL) and the second is a Single Slope Solar Distiller with Cement Layer (2 cm) and Cement Cylindrical Fins (SSSD-CL&CCF). Cylindrical fins are made of cement with a diameter of 1.5 cm and a length of 3 cm. The results showed that SSSD-CL&CCF produced drinking water at a rate of 4.52 kg/m²/day while SSSD-CL produced only 3.46 kg/m²/day, which is 30.64% more compared to SSSD-CL&CCF. These results demonstrated that the drinking water produced by SSSD-CL improved by incorporating the cement cylindrical fins with the cement layer as low-cost and available sensible thermal energy storage materials. Also, Cement cylindrical fins were used, which increased the thermal and exergy efficiency by 31% and 56.7%, respectively.

KEYWORDS:

• Distilled water
• solar distiller
• cement layer
• cement cylindrical fins
• energy storage

Nomenclature

$A_{\mathit{ab}}$	=	Absorber area, m2
$\mathit{E}{x}_{\mathit{input}}$	=	Input exergy energy, W
$\mathit{E}{x}_{\mathit{output}}$	=	Output exergy energy, W
${\dot{m}}_{\mathit{dw}}$	=	Distillate yield, kg/m2 h
$h_{\mathit{fg}}$	=	Latent heat, J/kg
$T_a$	=	Ambient temperature, oC
$T_w$	=	Water temperature, oC
I(t)	=	Solar rays intensity, W/m2
${\mathit{\eta }}_{\mathrm{daily}.\mathrm{exe}}$	=	Daily exergy efficiency, %
${\eta }_{\mathit{daily}.\mathit{th}}$	=	Daily thermal efficiency, %
Abbreviations	=
CSS	=	Conventional Solar Still
HSD	=	Hemispherical Solar Distiller
PCM	=	Phase Change Material
SS	=	Solar Still
SSSD-CL	=	Single Slope Solar Distiller with a Cement Layer
SSSD-CL&CCF	=	Single Slope Solar Distiller with a Cement Layer and Cement Cylinder Fins
TSD	=	Tubular Solar Distiller

Disclosure statement

No potential conflict of interest was reported by the author(s).