1 Peer-reviewed (refereed or scholarly) journals-Articles are written by experts and are reviewed by several other experts in the field before the article is published in the journal in order to insure the article's quality.
One key component to an efficient walk-in cooler is its insulation. A standard walk-in cooler will have between 2 and 4 inches of Styrofoam insulation within its walls and a rubber sealing gasket around its door to help ensure that it is both airtight and well-insulated against the temperature of the air outside.
Definition of cooler. 1 : one that cools: such asa : a container for cooling liquidsb : refrigerator. 2 : lockup, jail; especially : a cell for violent or unmanageable prisoners.