High Temperature Air Dryers are used primarily with reciprocating air compressors or small rotary screw air compressor that do not have an aftercooler. When a compressor does not have an aftercooler the air the compressor produces is very, very hot. A Non-Cycling or Cycling Dryer is not designed to handle the elevated approach temperature without using mathematical calculations to properly size the dryer. A High Temperature Air Dryer is designed to handle the high approach temperature and in all but extreme cases you can size your High Temperature Air Dryer by how many CFM your air compressor produces.