This may be achieved directly or through a heat exchanger.

The tank has a built in heat exchanger to heat domestic cold water.

Many metal collectors are installed as part of a sealed heat exchanger system.

Radiators and convectors are heat exchangers designed to transfer thermal energy from one medium to another for the purpose of space heating.

After being heated in the panels, the HTF travels to the heat exchanger, where its heat is transferred to the potable water.

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.