This is an improvised version of Internally Heated Air Dryer where purge air loss is very very low due to regeneration is achieved by dry air at low pressure and at high temperature. To achieve this heaters are provided to heat the purge air to around 180 Deg C, which enhances its moisture carrying capacities. This hot purge air at low pressure is passed through the desiccant bed to regenerate with small quantity of purge.
