- Refrigerators use the cooling effect of evaporation. In the refrigerator on the right, the process works like this:
- In the pipes in the freezer compartment, a liquid called a refrigerant evaporates and takes thermal
- energy from the food and air.
- The vapour is drawn away by the pump,
- which compresses it and turns it into a
- liquid. This releases thermal energy, so
- the liquid heats up.
- The hot liquid is cooled as it passes
- through the pipes at the back, and the
- thermal energy is carried away by the air.
Overall, thermal energy is transferred from the things inside the fridge to the air outside.