The primary function of a refrigerator is to remove heat from its interior, rather than adding cold. It does this through a process called thermodynamics, specifically by transferring heat from the inside of the refrigerator to the outside.
The cooling process in a refrigerator involves a closed-loop system of refrigerant gases that undergo compression and expansion. Here's a simplified explanation of how a refrigerator works:
Compression: The refrigerant gas is compressed, which causes it to become hot and high-pressure.
Condensation: The hot, high-pressure gas then flows through a set of coils located on the back or bottom of the refrigerator. As it loses heat to the surrounding air, it condenses into a liquid state.
Expansion: The high-pressure liquid refrigerant passes through an expansion valve, where it rapidly expands, causing it to become cold and low-pressure.
Evaporation: The cold, low-pressure refrigerant then flows through another set of coils inside the refrigerator's insulated compartment. As it absorbs heat from the interior of the fridge, it evaporates back into a gas state.
By removing heat from the inside of the refrigerator and releasing it outside, the interior of the fridge cools down, maintaining a lower temperature to keep food and beverages fresh.
So, while we often refer to a refrigerator as "adding cold," it is more accurate to say that it removes heat from the interior to create a cooler environment. This process allows us to store perishable items at lower temperatures, extending their shelf life and keeping them safe for consumption.