A University of Miami College of Engineering researcher has one goal: To help modern cargo ships go green.
This, however, is no easy feat. The World Shipping Council estimates that 6,000 container ships travel the world’s oceans every day, each bringing the risk of air pollution, oil spills, underwater noise, and wildlife collisions along with it. Depending on their size, cargo ships can also consume between 150-400 metric tons of fuel per day.
GeCheng Zha, a professor of aerospace engineering and the director of the Aerodynamics and Computational Fluid Dynamics Lab at the University of Miami wondered: What if these ships were powered by wind?
Of course, traditional wind sails could not handle the demand of today’s shipping industry, but a new type of sail definitely could. So Zha has set out to create stationary cylinder sails that promise to reduce ship fuel consumption (and cost) by up to 90%.
“What’s old is new again,” Zha said in a statement. “With the technological advancements of today, wind-assisted propulsion is an efficient alternative to diesel engines. And the major advantage is that it’s environmentally friendly — an effective way to decarbonize the shipping industry that’s responsible for about 3% of global greenhouse gas emissions.”
To achieve this, Zha’s giant cylinder sails would be mounted on the decks of cargo ships. These cylinders would suck in, pressurize, and eject air in different directions, generating ‘thrust,’ or momentum.
Each cylinder is designed to be several stories high but would be lowered to allow ships to pass beneath bridges and navigate through ports and can be retrofitted to be added onto nearly all existing ships.
Though Zha has published his research through the University of Miami, his invention is being developed through a startup: CoFlow Jet.
Zha’s cylindrical designs use a twist on the Flettner rotors developed in the 1920s. Flettner rotors are large rotating cylinders that produce thrust at the proper angles when air passes over them. Zha’s cylinders, however, do not rotate.
Rather, the cylinder takes in a small amount of air from the intake, then pressurizes it with a device called an impeller, and then expels the air through an outlet to generate a pressure imbalance.
This creates a substantial amount of thrust and is extended through the full length of the cylinders — which, as a reminder — are several stories tall.
On large cargo ships, Zha said the cylinders could cut fuel consumption by as much as 50% — and by up to 90% on smaller ships.
Though he is still in the design and simulation phase of these sails, Zha is confident in his work to redefine sails for the modern age.
“The shipping industry has had a tendency to resist change because diesel engines are so powerful,” Zha said. “But now, with pressure mounting, either willingly or unwillingly, it will have to change.”
The pressures he speaks of are rising fuel costs, as well as increasing government regulation from the International Maritime Organization requiring shipping companies to go carbon neutral “by or around” 2050.
According to the University of Miami, similar technology is already being used on some vessels — about 30 cargo ships out of a global fleet of about 60,000 utilize wind propulsion through sails made of aluminum, fiberglass, or carbon fiber.
By the end of this decade, the International Windship Association estimates that nearly 11,000 ships may be utilizing wind propulsion.
And Zha believes his cylindrical designs to be “much more efficient” than existing sails, adding, “We would be capable of achieving greater thrust.”
As his research gains speed alongside the urgent need to green the shipping industry, Zha’s next step is to secure funding to develop a prototype.
“We’ll get there,” he said in a statement. “With about 90% of the world’s trade traveling by ship, this technology is a ‘windfall’ of an idea.”
Header image courtesy of CoFlow Jet
