Eureka!

Into the Drink

Building the ultimate solar-powered water purifier

By Cory Nealon and Sally Jarzab

Perhaps you’ve seen celebrity adventurist Bear Grylls transform foul liquids into drinkable water using little more than sunlight and plastic sheeting. Now, a UB-led interdisciplinary team of researchers has turned this rudimentary survival tactic into a highly productive yet still inexpensive method to make contaminated water, or even saltwater, potable. The advancement could help to address drinking water shortages in developing or disasterstricken regions.

Called a solar still, this type of contraption is nothing new, but current models tend to be inefficient and costly to build. With its innovative addition of a carbon-dipped paper surface that both soaks up and heats up liquid, this one can produce 3 to 10 liters of water a day. That’s up to three times the output of commercial solar stills of similar proportions (about the size of a mini-fridge). Because the new design forgoes pricey optical concentrators, like mirrors and lenses, it costs dramatically less to make.

Illustration by Robert Wilder, BFA ’02

Here’s how it works:

A: A layer of porous paper absorbs water like a napkin, while its black carbon coating attracts and absorbs solar energy to vaporize the water. A layer of polystyrene foam underneath the paper provides insulation and buoyancy.

B: A clear, lightweight structure traps the water vapor as it rises, then cools and condenses.

C: A separate chamber collects the distilled liquid, now free of salt and contaminants. Cheers!

Qiaoqiang Gan

Qiaoqiang Gan, associate professor of electrical engineering in UB’s School of Engineering and Applied Sciences, was lead researcher on the project.