Design, fabrication and performance analysis of an improved solar still

► Temperature difference, Tw − Tc is one of the key parameters which effects on P. ► Water production cost one-third cheaper than basin-type & about 5% of the old one. ► Evaporation MTCs and HTCs were higher than those of condensation. ► Convection HTCs were much lower than those of evaporation/condensation. ► A linear relation is newly found between the total HTCs and MTCs.