LAUSR

Abstract The urgent need for fresh water remains a strong driver for reverse-osmosis (RO) desalination, but the systems are energy-inefficient and produce significant green-house gas emissions. This motivated our research, which introduces and investigates a novel concept for wind-driven RO desalination. It is based on the Coandă effect, applied periodically by blowing slots on a spring-stabilized vertical cylinder, to produce reciprocating motion that drives RO piston pumps. The Coandă-based Reciprocating (CoRe) system converts wind energy directly to mechanical pumping energy thereby eliminating generator and motor inefficiencies. A small-scale (2-meter high) system was constructed and evaluated in an open-jet wind tunnel. It delivered 2 to 6 bars of water pressure with a net power efficiency of up to 4% depending on wind speed and circulation control parameters. A mathematical model of the system produced excellent correspondence with the experimental data. It was determined that the experimental setup and slot design biased the results negatively and model predictions based on published Coandă data indicated net power efficiency of 20%. It was also determined that the slot design details had a decisive effect on performance.