Efficient and low-cost solar desalination device with enhanced condensation on nail arrays

Portable solar desalination is attracting increasing attention in recent years, due to its off-grid operating ability. Despite considerable progresses in solar evaporation, the inefficient condensation in air and exorbitant water production cost strongly limit the real applications. Here, we propose a solar desalination device with cheap brass nail arrays as effective condenser. With reduced evaporator-to-nail distance, vapor flux concentration at nail tip and vertically aligned surface of nail body, the vapor diffusion, condensation and condensate shedding can be enhanced simultaneously. Guided by a comprehensive modeling of the vapor transport, an optimized device was fabricated and tested. A solar-to-water efficiency of 51.13 % was demonstrated with nail array condenser, which was 10.24 % higher than that with conventional plate condenser. In addition, all the selected materials are cheap and durable. Due to the high energy efficiency and low cost, this design is promising to relieve the water shortage in off-grid regions.