The question is, how do they extract the water?

There are two circulating fans, a small one on the internal circuit
which blows through a resistance heater and then to the clothes, the
airflow circuit on the one I looked at used the door as a plenum.
After it leaves the clothes the moist air passes into an aluminium
cross flow heat exchanger. A larger fan blows ambient air in over the
secondary side of this and vents to the room. As the moist air cools
below its dew point in the heat exchanger it drips into a container,
there is also the option to take a drain to waste. The internal
circulation fan is much smaller than the heat exchanger fan.


Snore.. but true. Sucks cold air in through metal heat exchanger. Blows
hot wet air through other side of exchanger. Condensation occurs. Drained
off (into removeable tank or plumbed to drain). Hot dry air back into room.
Makes soft noise. Baby sleeps.