Thermal analysis of a closed loop inclined wick solar still (CLIWSS) with an additional heat storage water reservoir

Abstract

The authors proposed a closed loop inclined wick solar still (CLIWSS) containing an additional heat storage water reservoir. A reservoir is used to hold the hot water that exits the inclined wick solar still before being pumped back into the solar still as an intake. The cycle runs in a closed loop so that warm water is consistently fed into the still. A thermal model of the proposed CLIWSS has been created to determine the hourly/daily/monthly distillate output produced by CLIWSS. The model helps to find the temperature of exit water from solar still and the transient temperature of tank water. The proposed model has been experimentally verified. The performance of CLIWSS has been computed for the months of December and May for Jodhpur, India (23.23oN, 73.02oE). The proposed solar still produces more output than the typical inclined wick solar still (IWSS). The storage tank enhances the nocturnal production of distilled water. The maximum hourly distillate output produced by proposed still for May and Dec. is 1.025 L/m2/h and 0.556 L/m2/h, respectively. The total daily distillate output produced from the proposed still for summer (May) and winter (Dec.) is 8.432 L/m2 and 3.618 L/m2, respectively. The daily distillate output produced by CLIWSS in May and December is about 115% and 98% more than conventional SS. The total daily efficiency of the CLIWSS for summer is 64.1%, which is about 90.8% more than the conventional IWSS. The flow rate of water has a minimum effect on the output; when increased from 7L/h to 20L/h the decrease in the hourly output of CLIWSS is only 2%. At a 10% interest rate annually, the cost of the water produced by the proposed still is Rs 0.836/Lm2 (US$0.0104).