Clothes dryer

A clothes dryer (tumble dryer, drying machine, drying device, or simply dryer) is a powered household appliance that is used to remove moisture from a load of clothing, bedding and other textiles, usually after they are washed in the washing machine.

Many dryers consist of a rotating drum called a "tumbler" through which heated air is circulated to evaporate moisture while the tumbler is rotated to maintain air space between the articles. Using such a machine may cause clothes to shrink or become less soft (due to loss of short soft fibers). A simpler non-rotating machine called a "drying cabinet" may be used for delicate fabrics and other items not suitable for a tumble dryer. Other machines include steam to de-shrink clothes and avoid ironing.

Tumble dryers continuously draw in air from their surroundings and heat it before passing it through the tumbler. The resulting hot, humid air is usually vented outside to make room for more air to continue the drying process.

Tumble dryers are sometimes integrated with a washing machine, in the form of washer-dryer combos, which are essentially a front loading washing machine with an integrated dryer or (in the US) a laundry center, which stacks the dryer on top of the washer and integrates the controls for both machines into a single control panel. Often the washer and dryer functions will have a different capacity, with the dryer usually having a lower capacity than the washer. Tumble dryers can also be top loading, in which the drum is loaded from the top of the machine and the drum's end supports are in the left and right sides, instead of the more conventional front and rear. They can be as thin as 40 centimetres (16 in) in width, and may include detachable stationary racks for drying items like plush toys and footwear.

These centrifuge machines simply spin their drums much faster than a typical washer could, in order to extract additional water from the load. They may remove more water in two minutes than a heated tumble dryer can in twenty, thus saving significant amounts of time and energy. Although spinning alone will not completely dry clothing, this additional step saves a worthwhile amount of time and energy for large laundry operations such as those of hospitals.

Just as in a tumble dryer, condenser or condensation dryers pass heated air through the load. However, instead of exhausting this air, the dryer uses a heat exchanger to cool the air and condense the water vapor into either a drain pipe or a collection tank. The drier air is run through the loop again. The heat exchanger typically uses ambient air as its coolant, therefore the heat produced by the dryer will go into the immediate surroundings instead of the outside, increasing the room temperature. In some designs, cold water is used in the heat exchanger, eliminating this heating, but requiring increased water usage.

In terms of energy use, condenser dryers typically require around 2 kilowatt hours (kW⋅h) of energy per average load.

Because the heat exchange process simply cools the internal air using ambient air (or cold water in some cases), it will not dry the air in the internal loop to as low a level of humidity as typical fresh, ambient air. As a consequence of the increased humidity of the air used to dry the load, this type of dryer requires somewhat more time than a tumble dryer. Condenser dryers are a particularly attractive option where long, intricate ducting would be required to vent the dryer.