US Patent 11092394 Automated control of heat exchanger operation

An indirect heat exchanger has two airflow paths and an airflow generator to draw air through the airflow paths. A fluid conduit passes through the heat exchanger such that a cooling region is positioned within each of the flow paths. A dispenser is positioned to dispense evaporative liquid on one of the cooling regions. The dispenser operates in a wet mode and a dry mode. A controller regulates airflow through the first flow path and the second flow path, and also controls the operation of the dispenser. In this way, the controller may operate the airflow paths independently such that the airflow through a flow path operating in the dry mode is greater than that of the flow path operating in the wet mode.