Abstract
This experimental work focuses on the effect of using an internal cooling coil under a cover glass of basin solar still in order to increase solar productivity. The data collected during the climatic conditions of September and October months in Riyadh, Saudi Arabia is used in this work. The average ambient temperature is recorded around 37 degrees C (+/- 2 degrees C) at noon. The passing water through an internal cooling coil is cooled by a radiator heat exchanger, similar to those used in vehicles. The internal cooling coil used as an additional condensation surface with a cover glass. The droplets formed on the internal cooling coil by condensation are collected by a collector pipe in order to run down into a distillation channel. The solar parabolic trough and external film cooling technique is selected in this experimental setup to see its impacts on the internal cooling coil efficiency. Our topic of research on the internal cooling may be regarded as a new experimental technique to improve the productivity of the passive solar still by 25%. The modified solar still using the above techniques combined together increases the efficiency by 20.8% over the conventional solar still.