GAINESVILLE, Fla. — Think of it as a kind of chemical clothes wringer.
Universityof Florida engineers have developed a compound that forces clothes inthe washer to shed 20 percent more water during the spin cycle than innormal conditions. The result: A load of clothes dries faster in thedryer, saving energy — and reducing homeowners’ electricity bills andtime spent in the laundry room.
“We feel it’s very cost-effectiveresearch and convenient for consumers,” said Dinesh Shah, a professorof chemical engineering and director of the UF Center for SurfaceScience and Engineering.
Shah and Daniel Carter, a doctoralstudent in chemical engineering, will publish their second articleabout their research this month in Langmuir, a surface science journal.UF has applied for a patent on the research, which was funded with$200,000 from Procter & Gamble, a major manufacturer of laundrydetergent and related products.
More than 56 percent of Americansown electric dryers, with a typical dryer handling 300 loads per year,Carter said. With the average load requiring from 2.7 to 3 kilowatthours of electricity, that means drying clothes equates to 5 percent oftotal residential electricity consumption, costing $2.6 billionannually, Carter said.
A conservative 10 percent reduction indrying times would save consumers $266 million annually. But Shah andCarter say they can do better than that.
Their invention: A water-shedding compound created from a mix of common detergents and fabric softeners.
Carterand Shah said the researchers’ key insight was that the spaces betweentiny fibers in the weave of fabrics comprise minute tubes, orcapillaries, which retain water due to surface tension. It’s the samephenomenon that causes a submerged straw to hold water when covered atthe other end and lifted out of the surface, Carter said.
Theresearchers reasoned that reducing this surface tension would reducethe water retained by fabric. They first tested this idea usingfinger-sized copper containers dotted with drain holes. Filled withfabric and water and placed in a centrifuge, the containers mimickedthe conditions of spin cycling washing machines – except that the waterloss and fabric retention could be easily measured.
When theresearchers discovered that some compounds apparently increased waterloss, they expanded their experiments to bigger fabrics and a realwasher and dryer. The dryer sits in a crowded lab on a scale, allowingCarter to compare different wet loads by weight to their total dryingtimes.
Their experiments revealed that one ratio of a commondetergent and fabric softener – five parts detergent, one part fabricsoftener – added before the spin cycle forced the clothes to shed 20percent more water than untreated clothes. The clothes then dried 20percent faster.
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