US Patent 9279619 Cooling tower with indirect heat exchanger

A heat exchange apparatus is provided with an indirect evaporative heat exchange section. The indirect evaporative heat exchange section includes a series of serpentine tubes, and an evaporative liquid is passed downwardly onto the indirect heat exchange section. The evaporative liquid is collected in a sump and then pumped upwardly to be distributed again across the indirect heat exchange section. An improved heat exchange apparatus is provided with a top and a bottom indirect evaporative heat exchange section including a series of serpentine tubes A secondary system to distribute evaporative liquid below the first indirect heat exchange section and a direct heat exchange section may be provided between the two indirect heat exchangers.