Abstract: A heat exchanger includes a housing including an inlet for receiving bulk solids, and an outlet for discharging the bulk solids, a plurality of spaced apart, substantially parallel heat transfer plate assemblies disposed within the housing, between the inlet and the outlet for heating the bulk solids that flow from the inlet, through spaces between the heat transfer plate assemblies, and at least two gas handling zones including a first gas handling zone and a second gas handling zone spaced from the first gas handling zone, the two gas handling zones disposed between the inlet and the outlet for entry of a pulsed flow of air into the housing and around the bulk solids and for exit of the pulsed flow of air from the housing.