An air conditioning system includes a dehumidifier, a regenerator, and a refrigeration system. The dehumidifier removes water from a first airflow using a liquid desiccant. The regenerator transfers water from the dilute desiccant into a second airflow. The refrigeration system can be selectively used to provide heat to the desiccant in the regenerator to more effectively remove the water from the dilute desiccant. An external heat source can also be used to heat the desiccant in the regenerator to more effectively remove the water from the dilute desiccant. The refrigeration system and the external heat source can each be used separately to heat the desiccant, or the desiccant can be heated by both heat sources simultaneously.