Cutting refrigerators' wasted energy
Open refrigerators and store display cases are bastions of wasted energy. Now, researchers say there's a way to efficiently cool the units by turning the temperature up a notch.
Tue, Nov 24 2009 at 3:17 PM
Photo: ZUMA Press
Just in time for Thanksgiving and turkey consumption galore, scientists have worked out the solution to a nagging kitchen conundrum: our wasteful tendency to leave the refrigerator door open.
Mechanical engineers at Kettering University in Flint, Mich., have spent years searching for ways to cut the energy gobbled up by refrigerators and open store display cases, the Associated Press reports.
According to recent findings, the key is to slow down the air in the refrigerator. A team headed by mechanical engineering professor Homayun Navaz turned down the velocity of cold air and raised the temperature to 32 degrees in a refrigerated display case. The result is colder food, according to the school's Web site.
"By reducing the velocity by 30 percent, infiltration was reduced by 12 percent and the power required was reduced by 13 percent," school officials noted.
Navaz said people mistakenly assume that faster airflow leads to better refrigeration, when in fact the opposite is true. "You would think more air coming faster would work better, but interestingly, the decreased velocity improved infiltration, which resulted in the food being one degree colder than before," he said in a statement.
Navaz, along with doctoral student Mazyar Amin and University of Washington professor Dana Dabiri, conducted 3,000 tests before coming up with the findings. As part of their research, they constructed a 15-foot tall air circulation simulator. The Department of Energy along with the California Energy Commission and California Edison contributed funding.
So far, Navaz said some manufacturers have made changes based on his research. The next objective is to control the turbulence of cold air, which could help "achieve another 10 to 15 percent improvement in energy efficiency," he said.
Using less energy translates into cost savings, and Navaz said the state of California could save $13 million by following his protocol. It also reduces carbon emissions, he said. In California, that could translate to a 48,783-ton reduction in carbon emissions each year.
"There is a potential for huge payoff," he added. "Just multiply our results by the number of display cases used statewide, nationwide, and worldwide."