SOLMED: heat transfer characterization

摘要

Solar multi-effect desalination (SOLMED) is a new technology based on low-temperature multi-effect distillation (LT-MED). The project aims at sea water desalination on vertical polymer tubes using thermal solar energy, or low-grade thermal waste energy. This paper presents experimental results of a test rig with a single polyolefin tube of 70m thick. Hydrodynamic and thermal tests were carried out in order to characterize the heat transfer. It was found that salt water flow on the outer surface of the tube improves the falling film wetting over time. Results of the overall heat transfer coefficient are presented and compared to other studies. Achieved values ranged from 1,300 to 2,600W/m(2)K. Finally, two new correlations were developed from the experimental data to predict heat transfer coefficients for film evaporation outside the tube and dropwise condensation inside the tube.