A refrigerator is a machine for keeping things cold. It is sometimes called a fridge or an icebox. It is normally maintained at 4-5 degree Celsius for household use. People put food and drinks in it, to keep those items cold or good (unspoiled) for a longer time. A refrigerator has a heat pump. It takes heat away from the air inside the fridge. The heat gets added to the air outside. The heat pump is usually driven by an electric motor.