Extraction of drinking water from a modified tubular solar still integrated with straight tube and spiral tube flat plate collector

Solar stills have been used for water distillation for a long time; the technology is well matured, however, there is huge scope to improve their productivity further. The present research work is aimed at improving the productivity of the solar still by using a newer design -Tubular Solar Still (TSS), and integrating it with Flat Plate Collectors (FPC) with straight tube (TSS-STFPC), spiral tube (TSS-SPFPC) absorbers. The experimental set-up was designed, developed and installed at Nagpur, India. The experimental studies were conducted which compare the modified TSS to an unmodified baseline configuration. Results show the TSS-SPFPC configuration increased freshwater productivity by 14.5% over the TSS-STFPC at a flow rate of 1.5 L/h. In addition, an economic analysis shows that the lowest cost for freshwater production of 0.00373 USD per liter comes from the spiral tube flat plate collector configuration. The quality assurance of distilled water was also done in terms of pH measurements, which showed an increase from 6.4 (saline water) to 7.02 (distilled water).