Thermal performance enhancement of a modified pyramid distiller using different modifications with low-cost materials

•A v-corrugated basin, black cotton fabric, and paraffin wax were used in solar distiller.•Carbon nanoparticles were added to paraffin wax to enhance its properties.•Exergy and energy efficiencies were evaluated.•Water yield and thermal efficiency were enhanced by 76.9% and 101.5%, respectively.•The save in the total yield's cost per liter was 29.7%.