Tumble Dryer
Tumble Dryers are the standard dryers that don’t have lots of bells and whistles and are still the most prevalent type on the market today. They operate by pulling in cool, dry air that is around them and heating it before pushing it inside to your clothes and then to outside the home using a vent. To keep the level of moisture consistent amongst the items inside the drum will turn, or tumble, to put air in-between the items. This type of drying process causes some articles of clothing to shrink depending on their material and delicate items may be torn if put in with a larger load.
Condenser Dryer
Condenser dryers operate in much the same way as the conventional tumble dryer with a few small differences. Instead of exhausting the air to outside of the home it will use a heat exchanger to cool the air and condense the water vapor into a drain pipe or collection tank. Since this process only cools the air using internal air or water it will not dry the items as well as a traditional dryer and can take much longer. Condenser dryers are normally favored only where ducting to the outside is difficult to accomplish.
Heat Pump Dryer
Heat Pump dryers are even rarer than the condenser dryer though they work in a similar manner; a heat pump is required for this model to work. Instead of using the heat exchanger to cool the air down a heat pump will fill that role here. The hot humid air is passed into the heat pump where the cold side will condense the water vapor and the hot side will reheat the air afterwards to be reused. This allows the dryer to avoid using ducts and is actually more efficient than condenser and traditional tumbler dryers.