Why does it take longer to charge in a refrigerator or freezer than ice and water?
When the cooling pack is submerged in a container filled with ice and water, the pack is completely surrounded on all sides by a colder temperature. When the pack is laid on a shelf, only one side is touching the shelf, while the open side is exposed only to cooler air. Water is the beat thermal transfer medium while air is very poor at transferring cool or warm energy. The quickest method to charge the cooling pack is the ice and water method. This is also the feature that makes this technology man-portable for in-field use when electricity is impractical.
