Enhancing the Solar Still Performance Using Nanofluid Based Volumetric Absorption Solar Collector and Solar Pond An Experimental Investigation

Abstract

The aim of the present research work is not only to enhance the diurnal distillate output but also to generate nocturnal distillate and, in turn, enhance the performance of the solar still. In the present work, a novel nanofluid-based volumetric absorption solar collector (NBVASC) has been employed for efficiently harnessing the solar energy and supplying the same to solar still during sunshine hours for improving its diurnal production rate. A convective solar pond has also been used for supplying the stored sensible thermal energy to the basin of the solar still via heat exchangers during the non-sunshine period to produce the nocturnal distillate, which makes the system a round-the-clock unit to produce potable water. The research work was done in a proper sequence and hence the complete research was done in three phases. In the study s first phase, a novel nanofluid-based volumetric absorption solar collector (NBVASC) was fabricated to provide supplementary thermal energy to the modified solar still during sunshine hours. It was fabricated by constructing a shallow container, filling it with nanofluid and covering its top surface with two closely spaced transparent glass covers. The base and sidewalls of the solar collector have been insulated with polyurethane foam to reduce the thermal losses to the surroundings. Further, this foam was covered with a 1mm thick galvanized iron sheet to protect this insulation foam from weather conditions. A serpentine type of copper pipe heat exchanger (circulating ethylene glycol-based water-soluble heat transfer fluid, using a 12V DC pump having a rated power of 19 W) was also placed within the NBVASC to exchange the absorbed thermal energy from the solar collector to the water in the still. The NBVASC was filled with nanofluid, which was prepared by using a small amount of used engine oil acquired from a four-stroke diesel engine. After filtering the resin, sludge etc., with a cotton cloth, the filtered oil was then again refined with 0.7and#956;m filter paper.