Thermo-physical characteristics of passive double slope solar still loaded with MWCNTs and Al2O3-water based nanofluid

Abstract

In recent times, with advances in science and technology, nanaofluids attract a lot attention for their use in solar thermal systems. In this paper, an attempt have been made to study the thermo-physical characteristics of passive double slope solar (DSSS) still using multi wall carbon nanotubes (MWCNTs) and aluminium oxide (Al2O3)-water based nanofluids. Analysis have been carried out by developing thermal modelling of the proposed system for optimized fluid (basefluid/nanofluid) mass of 35 kg and three different concentrations (0.04%, 0.08%, and 0.12%) of Al2O3 and MWCNT nanoparticles. Significant enhancement in natural convective, evaporative heat transfer coefficients (HTCs); and productivity of passive DSSS has been obtained by incorporating Al2O3 and MWCNT nanoparticles. Due to better thermo-physical properties of nanofluids, increase in temperature difference between basefluid and nanofluid is found to be around 2 °C −3°C higher with MWCNT nanoparticles. It drives further significant rise in evaporative (Al2O3 42.6%; MWCNT 65.3%), natural convective (Al2O3 52.1%; MWCNT 58.1%) HTCs as well as productivity of the system.