Abstract: A spacer for use in stacking a plurality of cases containing a quantity of product on a pallet to form a pallet assembly and to facilitate heat transfer to or from the product is described. Installations for retaining a quantity of product at a desired temperature including a storage warehouse space including a rack-aisle heat transfer system incorporating pallet assemblies including spacers of the present disclosure are also described. The spacer of the present disclosure is useful to transfer heat to and from a quantity of warehouse product through both conduction and forced convection. The spacers provide an airflow path through at least one airflow channel between opposing sides of the pallet assembly so that airflow is not lost through sides adjacent to the opposing sides of the pallet assembly. The spacers further provide a consistent support surface for cases positioned above and below the spacers.