A refrigerator works on the principle of transferring heat from the inside to the outside, thereby cooling the interior compartment. It achieves this through a combination of several key components and processes. Let's go through the basic steps of how a refrigerator works:
Compressor: The refrigeration process begins with the compressor, which is typically located at the back or bottom of the refrigerator. The compressor is a motor-driven pump that compresses a refrigerant gas (often a hydrofluorocarbon or HFC) into a high-pressure, high-temperature gas.
Condenser coils: The compressed gas, now in a high-pressure state, flows through a network of coils located on the back or bottom of the refrigerator. These coils are known as the condenser coils. As the hot gas flows through the coils, it releases heat to the surrounding air, causing the gas to condense into a high-pressure liquid.
Expansion valve: The high-pressure liquid refrigerant then passes through an expansion valve, a small orifice that reduces its pressure suddenly. This process causes the refrigerant to expand and evaporate, turning it into a low-pressure, low-temperature gas.
Evaporator coils: The low-pressure gas now enters the evaporator coils, which are usually located inside the refrigerator's main compartment or freezer. As the refrigerant evaporates, it absorbs heat from the interior of the refrigerator, thus cooling the air inside.
Absorption of heat: The refrigerant inside the evaporator coils acts as a heat-absorbing agent. It draws heat from the food items stored in the refrigerator and transfers it to the low-pressure gas.
Return to the compressor: The low-pressure gas, having absorbed heat and cooled the interior, is then drawn back into the compressor to start the process all over again. This cycle continues as long as the refrigerator is running.
To address the second part of your question—how the moving parts inside the refrigerator prevent heat from escaping—we should understand that the primary goal of the refrigerator's design is to maintain a controlled environment inside the fridge, preventing heat from entering rather than actively preventing heat from escaping.
To accomplish this, the refrigerator is insulated using various materials like foam and rubber gaskets to minimize the transfer of heat from the external environment. The insulation helps to maintain a cool internal temperature, keeping the cold air inside and preventing warmer air from entering.
Additionally, the refrigerator door is equipped with a magnetic sealing mechanism. When the door is closed, the magnetic seals create an airtight barrier, preventing warm air from seeping into the refrigerator and compromising its cooling efficiency.
By efficiently removing heat from the interior and preventing the influx of warm air from the outside, the refrigerator can maintain a consistently cool temperature to preserve the freshness of perishable items stored within.