DefinePK

Abstract

Potable water is a basic need for the habitants of an area. In Pakistan, almost 53% of total population does not have access to safe and sufficient drinking water because of brackish/saline water. The brackish/saline water could be economically desalinized by solar desalinization (distillation). To solve this problem, a solar still was designed, fabricated and installed at Agricultural and Biological Engineering Institute, National Agricultural Research Centre, Islamabad. The solar still was developed with mild steel sheet having 2 m2 area, the inlet water depth was kept 2 cm, angle of glazing (glass) was kept 150, and the basin base was painted black to absorb the solar radiation. The performance of the solar still was evaluated from June to December, 2011. The parameters measured/calculated were: ambient temperature, inlet water temperature, vapours temperature, basin water temperature, basin temperature, wind speed, solar radiation, and productivity (output) of the solar still. The average daily productivity of the solar still for months of June, July, August, September, October, November, and December was 5738 ml, 3937 ml, 2637 ml, 1837 ml, 2082 ml, 1620 ml, and 1510 ml, respectively. The productivity of the solar still was higher during the month of June (5738 ml) as compare to its productivity during the month of December (1510 ml), this was because of higher solar intensity during the month of June. The average productivity of solar still from June to December was 3000 ml and the overall efficiency was 22%. The average cost of desalination was predicted Rs 3.9 per litre.