Modeling and Analysis of Large-Scale Direct Contact Membrane Distillation and Parabolic Trough Concentrated Solar Power

Abstract

In arid regions worldwide, sea and brackish water desalination is the primary source of potable water. In Kuwait and the Gulf countries, co-generation plants combine seawater desalination and power generation. Thermal desalination is prevalent in these plants, with a more than 70% share. Similarly, electric power generation is dominated by fossil fuels that operate steam and combined cycle turbines. This study is motivated by the pressing need for sustainable and renewable sources for electricity generation and water desalination. It focuses on the design and performance analysis of largescale concentrated solar power (CSP) plants with a capacity of 111 MWe. The system utilizes parabolic trough solar collectors (PT) and molten salt energy storage tanks. It is combined with a direct contact membrane distillation (DCMD) system, which has a capacity of 100,000 m³/d. Design and analysis of the CSP system are conducted using the System Advisory Model (SAM), which utilizes daily average data on ambient temperature and solar radiation in Kuwait. The model generates the thermal energy load and the amount of electric power produced by the PTCSP system. This data is then used to design a large-scale DCMD plant that operates on feed and cooling water temperatures of 60 °C and 20 °C, respectively. The feed stream in the DCMD system flows across four elements in series, with a 5 °C drop in each component, while the cooling water flows in a parallel configuration. The system's design characteristics and model predictions align with previous literature. Estimates of the levelized cost for both systems are $0.83/m³ for desalinated water and $0.11/kWh for electric power. Both systems are envisioned as integral components of existing co-generation plants in Kuwait. The model and results provide insights into large-scale renewable energy plants and nonconventional desalination systems that utilize low-grade energy and heating steam from lowpressure turbines. A MATLAB code is used to design the DCMD system and assess model accuracy.