So my local DRMO has a few of these Portable Blood Bag chillers for sale, the interior dimensions are (HxWxD) 240mm x 460mm x 335mm, or approx. 9 1/2 inches (Top to Bottom) by 18 inches (Side to Side) by 13 inches (Back to Front)...
A 2.5 Gallon Corny keg, laying on its side would fit almost...