Experimental and Numerical Analysis of a Small-Scale Desalination System Using Humidification–Dehumidification Fed by Linear Fresnel Concentration

Access to freshwater is one of the major global challenges, driven by population growth, industrial development, climate change, and increasing water stress, particularly in economically constrained regions. In this context, this study designs, builds, and experimentally and numerically evaluates an indirect solar concentration desalination system (ICST) composed of a humidification–dehumidification (HDH) subsystem thermally powered by a Linear Fresnel Concentrator (LFC) under the appropriate technology paradigm. The methodology integrates an experimental campaign conducted under real climatic conditions in Bucaramanga, Colombia, mathematical modeling based on mass and energy balances, and the implementation of a TRNSYS simulation model validated through qualitative and quantitative analyses using absolute and relative errors. Results showed close agreement between experimental and simulated data, with daily freshwater production deviations of 0.53 and 0.65 L/day in tests 04 and 05, respectively, while mean relative errors remained below 5% for the main thermal and productivity variables. Experimentally, an average freshwater production of 1.13 L/h was achieved, with a production gain ratio (GOR) of 0.32 and a recovery ratio (RR) of 0.021, while maintaining total dissolved solids below 500 mg/L. Economic assessment estimated a production cost of $0.065/L, demonstrating the technical and economic feasibility of the system for decentralized small-scale applications in regions with high solar irradiance throughout the year.