Solar-powered charger, cooler buildings, better indoor gardens emerge from MIT science competition

SolarStruct created a foldable solar-powered phone charger that can fit inside a backpack.
SolarStruct created a foldable solar-powered phone charger that can fit inside a backpack.

School kids at soccer practice could use solar panels lying out in the field to charge their smartphones. A mix-in for concrete could keep buildings cooler longer, cutting the cost of air conditioning. A gel that dries to a crisp could soak up water and swell, transforming into a single-layer, mess-free base on which you can grow a garden indoors.

These are the visions of a better world from emerging engineers tackled at MADMEC, the annual design competition hosted by the Department of Materials Science and Engineering at MIT.

After submitting proposals in the spring and developing their projects over the summer, five finalists emerged. These teams presented their projects Friday afternoon, and judges from MIT, MIT-spinoff Ambri, and materials giants Saint-Gobain and Dow Chemical, picked the winning trio.

First prize: AquaFresco
The problem: Humans use gallons of water for household tasks, but ineffectively.
The solution: Ting-Yun Huang, Alina Rwei, and Chris Lai built a filter that could effectively absorb the oily, greasy bits in runoff water from dishwashing or laundry, so that both detergent and water can be recycled.

CoolCrete is a concrete mixture that could make for cooler buildings.

CoolCrete is a concrete mixture that could make for cooler buildings.

Second prize: CoolCreate
The problem: We spend a lot of energy cooling our buildings and the fact that they’re made of concrete only makes the problem worse.
The solution: Alan Ransil and Wenhao Sun found an additive for concrete which, when combined with regular building material in small quantities, could absorb the heat from outside the building during the day. “It’s like powdered sugar,” Ransil said. It’s cheap, abundantly found in the earth, and doesn’t alter the hardiness of the building material itself.

Hydragenics created a water-absorbent gel can help create indoor, rooftop and wall gardens.

Hydragenics created a water-absorbent gel can help create indoor, rooftop and wall gardens.

Third prize: Hydragenics
The problem: Roof gardens and indoor plants are friendly green oases indoors, but wouldn’t it be nice to cover a whole wall in plants? Unfortunately, roof gardens are expensive and difficult to build, needing layers of material and soil and supports to keep them up.
The solution: A water absorbent sticky gel that supports plants, makes for “one layer… a whole bunch of plants growing on top,” team member Brent Keller said. Ritchie Chen and Yu-Sang Yang were also members of this team.

Another finalist team — Sangtae Kim, Soon Ju Choi, and Wenbin Li of MechaTricity — made a device that converted mechanical energy to electrical energy. Such “piezoelectric” devices exist, but their combination, they contend has a far better efficiency.

SolarStruct created a foldable solar-powered phone charger that can fit inside a backpack.

SolarStruct created a foldable solar-powered phone charger that can fit inside a backpack.

But there was one device that was easiest to imagine being used immediately. Anna Cheimets and Olivia Hentz of SolarStruct created a foldable solar charger, by using off-the-shelf basic solar panels fitted onto a plastic 3D-printed base.

The duo zoned in on a sample target market: the over-committed teenager. Most of us don’t carry around solar chargers to juice up our phones on a daily basis, they said. But for a teenager who’s been texting all day, “It gives your phone an extra boost for that one last text message or to check Google Maps,” Hentz said.

The brightly colored foldable charger could be set out on a practice field or near a window during the sports practice or music lessons. Their flower shaped prototype is designed to catch the the sun’s rays from any angle, even as it moves across the sky. In performance tests, the team said, they were able to extract more power than a flat panel solar screen

Nidhi Subbaraman writes about science and research. Email her at nidhi.subbaraman@globe.com.
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