Heat exchanger

A heat exchanger is a device that takes heat from one place and moves it to another. It's like a giant bucket of hot and cold water- the hot water goes in one side and the cold water goes in the other side. The heat exchanger then shuffles the water around so the hot water goes to the cold side and the cold water goes to the hot side. That way, the heat from the hot water is moved to the cold water and the cold water cools off. Heat exchangers are used in machines like air conditioners, heaters, and car engines to help keep things at the right temperature.