Winter's Droplets: Creating Durable Condensation Management

Rebecca Winter
Rebecca Winter
Photo credit: Donna Rhoads Photography

Recent Mechanical Engineering and Mechanics (MEM) PhD graduate Rebecca Winter wants to change the way power plants and other facilities manage condensation. Motivated by a desire to create phase change systems with more efficient use of energy, Winter targeted better ways of condensing water that would be feasible in real-world applications. Her research, under the advisorship of Dr. Matthew McCarthy, PhD, associate professor of MEM, drew on concepts that have already been investigated on the micro- and nano-scale and extended the use of engineered surfaces to a size more practicable for industrial use today.

“The problem with a lot of the research in this field is that while micro-scale surfaces have been shown to dramatically enhance performance, they tend to be very fragile in practice,” says Winter. “Even if the surface is pretty durable and you can use it a couple of times, power plants last on the order of decades and they expect not to have to replace things, so it’s way outside of what is practicable for them. So I was looking to create something on the macro scale that built on previous work and had the potential to enhance performance over the decades-old technology that real power plants are using now.”

Ridged Surface
Winter's work has a unique ability to act like a water-loving hydrophilic surface during the liquid growth phase, and act like a water-repellant hydrophobic surface during the shedding phase. ACS Appl. Mater. Interfaces 2020, 12, 6, 7815–7825.

Winter’s work (available here and here) involves the use of a novel type of amphiphilic surface, which can be made at either the micro or macro scale, to channel condensation and improve droplet formation and shedding. The surface has narrow grooves of a hydrophilic metal surface with peaks coated in a hydrophobic material, allowing condensate to fill the channels until it reaches a critical size, and then move to the finned tips, where drops can more easily shed and make space for new liquid. “The surface has a unique ability to act like a water-loving hydrophilic surface during the liquid growth phase, and act like a water-repellent hydrophobic surface during the shedding phase.”

Winter, who graduated over the summer and began work for the NASA Glenn Research Center in Cleveland, OH, also holds a BS in Environmental Engineering from Columbia University and an MS in Mechanical Engineering from the University of Pennsylvania. “As an engineer, I see my role as seeking truth in a domain that can change the lives of real people for the better.” Her doctoral work at Drexel culminated with a study extending the use of amphiphilic surfaces to tubes, which is currently in preparation for manuscript submission.

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