A refrigerator is an household appliance used for keeping food fresh.The cooling effect of evaporation is used in a refrigerator.
The volatile liquid used is usually liquid ammonia or freon. Ammonia evaporates inside coiled copper tubes surrounding the freezing compartment, assisted by a pump which reduces the pressure. As it evaporates in these coils,the ammonia absorbs heat from the surrounding air,thus cooling the inside of the refrigerator and its contents.
The vapour produced is pumped away and compressed in a condenser where it condenses to liquid ammonia. The heat released during this condensation is quickly dissipated by an arrangement of cooling fins at the back of the refrigerator.
The liquid is recycled through the evaporator coil and the process is repeated, thus setting up a continuous circulation of liquid and vapour.