A refrigerator keeps food cold by moving heat from inside the cabinet to the surrounding room. It does not create cold; it removes heat using a circulating chemical called a refrigerant.
The process begins in the evaporator coils inside the refrigerator. There, the refrigerant is at low pressure and evaporates into a gas. Evaporation absorbs heat from the air and food inside the cabinet, lowering their temperature. A fan may circulate the cooled air throughout the refrigerator and freezer compartments.
The compressor then draws in the refrigerant gas and compresses it. Compression raises the refrigerant’s pressure and temperature. The hot, high-pressure gas flows through condenser coils, usually located behind or underneath the refrigerator. Heat passes from these coils into the room, causing the refrigerant to cool and condense into a liquid.
Next, the liquid refrigerant passes through an expansion valve or narrow capillary tube. Its pressure drops suddenly, making it cold enough to absorb more heat when it returns to the evaporator. This cycle repeats whenever the thermostat detects that the interior is becoming too warm. Insulation and tight door seals slow the entry of heat, allowing the refrigerator to maintain a low temperature efficiently.