Techno-economic and thermal assessment of an evacuated flat plate collector-driven direct contact membrane distillation system with localized heating

Renewable energy-powered desalination systems are one of the attractive, viable solutions to cater for the freshwater demand. This study presents the performance assessment of the energy utilization and freshwater production in solar-powered direct contact membrane distillation system with a validated mathematical model. The objective of this work is to estimate the freshwater production, energy collection, temperature polarization coefficient, overall efficiency and gained output ratio under different weather conditions in the Indian subcontinent. In this study, a nanofluid is used in the evacuated flat plate collector to enhance the thermal performance of the collector, and localized heating is incorporated along with the varying solar irradiation to assess the diurnally transient performance of the evacuated flat plate collector driven direct contact membrane distillation system. It is necessary to optimize the operating hours based on the various system performance metrics. The performance of the integrated system is examined for hourly variation of solar radiation and ambient condition for representative day of different months. The study reveals that the cumulative forenoon distillate flux is significantly lower than that produced in the afternoon, with the afternoon-to-forenoon flux ratio varying between 16.16 and 19.46. In addition, April, May and October are found to be best months for 8 h of operation of the integrated system due to the lowest specific energy consumption. Furthermore, the maximum overall efficiency is observed around 3:00 PM in all the months. In addition, a tentative cost analysis of such system with 1 m 2 membrane area depicted the levelized cost of water to be 0.049 USD/L.