An apparatus for cooling items, the apparatus comprising: a housing defining (i) a bay space, (ii) a plenum positioned above the bay space, (iii) a front air passage fluidly connecting a front end of the bay space to a front end of the plenum, and (iv) a rear air passage fluidly connecting a rear end of the bay space to a rear end of the plenum, wherein the bay space, the plenum, the front air passage, and the rear air passage collectively provide a closed-loop within which air is circulated within the housing, wherein the bay space includes a plurality of layers that are each configured to hold one or more rows of pallets of items to be cooled; a fan positioned within the plenum and configured to circulate air through the closed-loop provided by the bay space in the housing, the fan operable to (i) pull the air from the rear end of the bay space, through the rear air passage, and into the rear end of the plenum, and (ii) discharge the air into the front end of the plenum, through the front air passage, and toward the front end of the bay space; a first plurality of channels arranged within the rear air passage, each of the first plurality of channels defining a first fluid pathway that (i) is fluidly separate from other fluid pathways provided by others of the first plurality of channels and (ii) extends from a rear end of a corresponding layer of the plurality of layers to the rear end of the plenum, the first plurality of channels configured to, over their length, turn a direction of airflow from the rear end of the bay space to the rear end of the plenum; characterized by a second plurality of channels arranged within the front air passage, each of the second plurality of channels defining a second fluid pathway, each of the second plurality of channels defining a second fluid pathway that (i) is fluidly separate from other second fluid pathways provided by others of the second plurality of channels and (ii) extends from a front end of a corresponding layer of the plurality of layers to the front end of the plenum, the second plurality of channels configured to, over their length, turn a direction of airflow from the front end of the plenum to the front end of the bay space. a housing defining (i) a bay space, (ii) a plenum positioned above the bay space, (iii) a front air passage fluidly connecting a front end of the bay space to a front end of the plenum, and (iv) a rear air passage fluidly connecting a rear end of the bay space to a rear end of the plenum, wherein the bay space, the plenum, the front air passage, and the rear air passage collectively provide a closed-loop within which air is circulated within the housing, wherein the bay space includes a plurality of layers that are each configured to hold one or more rows of pallets of items to be cooled; a fan positioned within the plenum and configured to circulate air through the closed-loop provided by the bay space in the housing, the fan operable to (i) pull the air from the rear end of the bay space, through the rear air passage, and into the rear end of the plenum, and (ii) discharge the air into the front end of the plenum, through the front air passage, and toward the front end of the bay space; a first plurality of channels arranged within the rear air passage, each of the first plurality of channels defining a first fluid pathway that (i) is fluidly separate from other fluid pathways provided by others of the first plurality of channels and (ii) extends from a rear end of a corresponding layer of the plurality of layers to the rear end of the plenum, the first plurality of channels configured to, over their length, turn a direction of airflow from the rear end of the bay space to the rear end of the plenum; characterized by a second plurality of channels arranged within the front air passage, each of the second plurality of channels defining a second fluid pathway, each of the second plurality of channels defining a second fluid pathway that (i) is fluidly separate from other second fluid pathways provided by others of the second plurality of channels and (ii) extends from a front end of a corresponding layer of the plurality of layers to the front end of the plenum, the second plurality of channels configured to, over their length, turn a direction of airflow from the front end of the plenum to the front end of the bay space.