Energy and environmental performance of a new solar boiler with heat recovery for seawater desalination

This study proposes a new seawater desalination process using concentrated solar energy. Compared with conventional desalination technologies, the proposed process produces tap water with high energy efficiency and a lower environmental impact. The proposed process is based on a new type of solar boiler using solar energy concentrated via a "beam-down" optical system. To improve the productivity, the steam produced is used to feed an adapted multiple-effect distillation (MED) system. A complete process model from seawater and sun to tap water is proposed, coupling an in-house Python program for the solar boiler component and ProSim software for the MED component. Ancillary calculations concerning the pretreatment, post-treatment, and sizing of the components are performed using a spreadsheet program. The environmental impacts of the tap water production by the proposed system are evaluated using the life cycle assessment method. The theoretical feasibility of the proposed process is demonstrated by modeling a reference case, with an estimated annual productivity of 10,000 m(3) of tap water. According to the calculation, the energy performance is estimated at 1.57 kWh of electricity and 117.7 kWh of solar energy per cubic meter of tap water produced. An estimated land area of 3845 m(2) is required for the solar field. The life cycle assessment indicates that the performance of the proposed process is significantly improved compared with conventional MED, with an 84% reduction in the total impact according to the ReCiPe endpoint method. In addition, the proposed system displays a competitive environmental performance compared with reverse osmosis. The emissions of the new process are estimated at 2.36 kg CO2-eq per cubic meter of tap water produced versus 3.67 kg CO2-eq and 2.97 kg CO2-eq for low- and high-performance reverse osmosis, respectively. (C) 2022 Institution of Chemical Engineers. Published by Elsevier Ltd. All rights reserved.