Designing and constructing a solar thermal water desalination system: Evaluating the role of thermoelectric in enhancing evaporation and condensation process

This study presents the design and experimental evaluation of a solar thermal water desalination system enhanced with thermoelectric (TE) modules to improve both evaporation and condensation efficiency. A baseline passive system using only solar energy was constructed and tested under real environmental conditions. To address limitations in solar availability and enhance performance, thermoelectric modules were integrated in two configurations: (1) using only the hot side to support evaporation, and (2) utilizing both the hot and cold sides to simultaneously enhance evaporation and facilitate condensation. Five operational scenarios were tested—both under sunlight and in its absence—to isolate the individual and combined effects of solar heating and thermoelectric assistance. Results show that using only the TE hot side increased freshwater production by 41.56%, while simultaneous use of both sides improved production by 89.04% compared to the passive setup. The highest freshwater yield (14.11 L/m²·day) occurred when both solar and thermoelectric effects were utilized, and the highest thermodynamic efficiency (92.2%) was achieved under TE-only operation indoors. Energy balance analysis confirmed that vapor removal through cold-side condensation is a critical factor in maximizing overall efficiency. Unlike previous studies focused on electricity generation or complex materials, this work uses commercially available, low-cost components and provides a quantitative separation of thermoelectric contributions to evaporation and condensation. The findings demonstrate that effective thermal integration of TE modules can significantly improve freshwater output and system reliability, offering a practical solution for decentralized water production in off-grid or resource-limited areas.