An apparatus is provided for facilitating cooling of an electronics rack. The apparatus includes a heat exchange assembly mounted to an outlet door cover hingedly affixed to an air outlet side of the rack. The heat exchange assembly includes a support frame, an air-to-liquid heat exchanger, and first and second perforated planar surfaces covering first and second main sides, respectively, of the air-to-liquid heat exchanger. The heat exchanger is supported by the support frame and includes inlet and outlet plenums disposed adjacent to the edge of the outlet door cover hingedly mounted to the rack. Each plenum is in fluid communication with a respective connect coupling, and the heat exchanger further includes multiple horizontally-oriented heat exchange tube sections each having serpentine cooling channel with an inlet and an outlet coupled to the inlet plenum and outlet plenum, respectively. Fins extend from the heat exchange tube sections.