Performance Assessment of an Integrated Solar-Driven Direct Spray Evaporator for Artificial Seawater Desalination

An integrated solar-driven desalination system was developed to address increasing clean water demand using renewable energy for artificial seawater treatment. This study aimed to evaluate the performance of a combined evacuated tube heat pipe solar collector (ETHP-SC) and direct spray evaporator in terms of thermal behavior, distilled water productivity, and water quality improvement under outdoor conditions. Artificial seawater from NaCl, MgCl2, and potting soil extract was circulated through an ETHP-SC-plate heat exchanger and sprayed into a vacuum evaporator, with vapor condensed in water-cooled condenser during 8-hour daytime tests in September 2025. The ETHP-SC showed increasing instantaneous thermal efficiency from about 10-20% in the morning to around 60-80% when solar irradiance declined in the afternoon, while average distilled water production reached about 0.91 L/m2.h and was strongly governed by solar radiation and system temperature profiles. Distilled water exhibited substantial reductions in conductivity, TDS, and salinity compared with feedwater and brine, although TDS still exceeded drinking water limits and DOC removal remained limited due to volatilization and material leaching. The integrated ETHP-SC-direct spray evaporator effectively harnesses solar energy for desalination but requires further optimization or post-treatment to achieve potable water standard and enhanced organic removal.