Distillation; Heat and mass transfer; Purification of brackish water
The rate of distillate depends mainly on operating temperature, shape and material ofthe condensing cover. Further, it is important to study the behaviour of heat and mass transfer relations as a function of operating temperature, shape and material. For the present study two sizes of semi-cylindrical condensing covers with characteristic dimensions of 0.14 cm and 0.07 cm were used. The materials most common for condensing covers for distillation used were aluminium and copper. The studies were carried out under controlled environmental conditions. The operating temperature kept during the experiments was between 40°C to 80°C for both forced as well as natural mode. It was observed that the convective and evaporative heat transfer coefficient depends strongly on operating temperatures. The following results at operating temperatures of 40°C to 80°C were obtained: (1) there is an increase of about 15% in the evaporative heat transfer coefficient due to the size of the condensing cover; and (2) there is an increase of about 7.5% in the evaporative heat transfer coefficient due to a change in material.