Exploiting the Coanda= effect for wind-driven reciprocating RO desalination

The urgent need for fresh water remains a strong driver for reverse-osmosis (RO) desalination, but present-day 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 Coanda = effect, applied periodically by blowing slots on a spring-stabilized vertical cylinder, to produce reciprocating motion that drives RO piston pumps. The Coanda =-based Reciprocating (CoRe) system converts wind energy directly to mechanical pumping energy thereby eliminating generator and motor inefficiencies. A small-scale (2-m high) system was constructed and evaluated in an open-jet wind tunnel. It delivered 2-6 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 Coanda = data indicated net power efficiencies up to 20%. It was also determined that the slot design details had a decisive effect on performance. (c) 2021 Elsevier Ltd. All rights reserved.

Automated summary

The study introduced and investigated a novel concept for wind-driven RO desalination, the CoRe system, which converts wind energy directly to mechanical pumping energy, improving efficiency. Experimental results showed that slot design details play a crucial role in system performance.