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Ice-Free Refrigeration

Ice-Free Refrigeration: Dayton Company Uses UDRI Technology to Transport Anthrax Vaccine

A Dayton company is using a technology developed by the University of Dayton Research Institute to fight against the anthrax and bioterrorism scare.

The U.S. Army's Medical Materiel Agency, the Centers for Disease Control and Prevention and the U.S. State Department have ordered hundreds of ice-free refrigeration systems from Energy Storage Technologies Inc. to support emergency preparedness in homeland defense and to transport the anthrax vaccine to troops in the field.

"Orders have skyrocketed since the Sept. 11 terrorist attacks. The storage of these vaccines is very critical at this time," said Lloyd Huff, chief executive officer of Energy Storage Technologies Inc. in Centerville, Ohio. "The system is perfect for transporting temperature sensitive vaccines and life-saving medical supplies to anywhere in the world because the portable units will maintain a constant temperature for 40 or more hours on internal batteries." Vaccines are routinely maintained in remote spots around the globe with conventional, mostly kerosene-powered refrigerators and insulated iceboxes. The problem: These systems rely on ice and have inadequate temperature control to maintain vaccine storage conditions. In addition, their energy requirements prohibit portability.

Energy Storage Technologies Inc. has developed a portable solar or battery-operated refrigerator called the VaxiCool. It features a vacuum-insulated refrigerator, a vacuum-insulated vaccine carrying case and packets of phase change materials that provide the constant temperature. Designed and patented by retired UDRI senior research scientist Ival Salyer, the phase change material is chemically engineered to melt and solidify at a constant 41 degrees Fahrenheit, absorbing and then releasing latent heat with each conversion from solid to liquid and back again.

Unlike other solar refrigerators, this one operates on one low-wattage solar panel -- not a solar panel array -- and is backed up by a conventional 100-amp-hour battery that can be recharged using solar or any electric source -- even a car battery -- anywhere in the world. The vacuum panels insulate five to eight times better than polyurethane.

The standard version of the VaxiCool unit, about the size of a standard cooler, costs about $3,700. The smaller VaxiPac carrying case sells for about $250. UDRI holds a technology licensing agreement with Energy Storage Technologies Inc., which projects sales of $10 million through 2002.

The VaxiCool was originally designed for the World Health Organization's immunization program in underdeveloped countries, according to Huff. The World Health Organization requires that vaccines be held at storage temperature for 16 to 20 hours in devices that can operate without external power.

"Today, we're using the units to prepare for what was once unthinkable," Huff said. "The system provides safe distribution of heat-sensitive vaccines during natural disasters, military and civil defense emergencies. After Sept. 11, the focus has turned to emergency preparedness."

The University of Dayton Research Institute, which built production prototypes of the refrigerator in 1997, holds more than 75 domestic and foreign patents on phase change materials. The technology is being used in hot and cold packs, pizza-delivery boxes, an electric floor-heating system and microwave-heated clothing, such as earmuffs and scarves.

November 11, 2001


University of Dayton Research Institute

300 College Park
Dayton, Ohio 45469 - 0101

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