A plurality of inlet and outlet channels for receiving and exhausting respectively the flow of a heat exchange medium directed to the inlet channels are located adjacent a plate provided with generally parallel, elongated orifices extending in the direction of and in registration with the inlet and outlet channels. A heat exchange panel is disposed adjacent the plate on the side thereof opposite that of the channels such that the medium entering the input channels travels through the orifices of the plate to the heat exchange panel and then from the panel to and through the outlet channels.
