As snow, sleet, freezing rain and frigid Arctic air grip much of the nation, many people will spend dangerous amounts of time outside, shoveling snow, scraping ice or sledding. The chilling atmosphere can have a damaging effect on individuals. As the body attempts to conserve energy, it shuts off heat to the hands, fingers and toes, dropping the temperature to these extremities by 40 degrees F, thus making them susceptible to frostbite. A researcher at the University of Missouri-Columbia and W.L. Gore and Associates are developing a new glove containing flexible heat pipes that will solve this dangerous problem.
"This new glove will be lighter, thinner, warmer and more comfortable than anything on the market today," said Hongbin Ma, assistant professor of mechanical and aerospace engineering, who started on the project a year ago and recently completed a prototype of the glove. "We simply use the body heat from the upper arm to warm up the fingers during the wintertime."
Each glove, which will be made of polyester, contains five small heat pipes, one for each finger, that are about 14 inches long and 1 mm x 2 mm in the cross section. Each pipe consists of three sections: an evaporating section, which is attached to the upper arm area; an adiabatic section, which is between the finger area and the arm area; and the condensing section, which is attached to the finger area.
According to Ma, the heat is transferred to fluid in the glove through direct contact between the heat pipes and the individual's arm. The fluid, in turn, is vaporized and the vapors bring heat to the fingers. The vapor is then condensed back into the fluid, which flows back to the arm section through a wick structure embedded in the heat pipe. In this way, Ma says, the heat will continuously be transported from the arm to the finger.
"The heat transport is dependent on the temperature difference," Ma said. "When the temperature difference between the arm and fingers is higher, like it is during the winter, the heat transport capability will increase. When the temperature difference is low, such as when someone comes in from outside, the glove will automatically adjust the heat transfer capability."
Ma, who also is developing the same device for shoes, is the founder of MU's Research Consortium for Innovative Thermal Management, which develops novel low-cost cooling technologies and delivers the research results directly to the industry. The consortium is the first of its kind in the United States to focus on heat pipes and phase-changing cooling devices.
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