If your fridge emits a belch of vapor when the compressor shuts down, it's likely due to a phenomenon called "refrigerant boiling off." Let me explain the process step by step:
Refrigeration Cycle: A refrigerator operates on a refrigeration cycle that involves a refrigerant, which is a chemical substance with properties that allow it to absorb and release heat efficiently. The main components of the refrigeration cycle are the compressor, condenser, expansion valve, and evaporator.
Compressor: The compressor is a crucial part of the refrigeration cycle. It compresses the low-pressure, low-temperature gaseous refrigerant into a high-pressure, high-temperature gas.
Condenser: The high-pressure, high-temperature refrigerant gas then flows into the condenser, where it releases heat to the surroundings and condenses into a high-pressure liquid.
Expansion Valve: The high-pressure liquid refrigerant passes through the expansion valve, where its pressure is rapidly reduced. This causes a sudden drop in temperature, turning the liquid into a low-pressure, low-temperature mixture of liquid and vapor.
Evaporator: The low-pressure, low-temperature refrigerant mixture enters the evaporator, which is located inside the fridge. The evaporator absorbs heat from the fridge's interior, causing the refrigerant to evaporate into a low-pressure gas.
Vapor Belch: Now, when the compressor shuts down after its cycle, the pressure in the refrigeration system decreases. This sudden drop in pressure can cause any remaining liquid refrigerant inside the evaporator to rapidly evaporate into a gas. The sudden expansion of the refrigerant can create a visible "belch" of vapor, which might be observed as a burst of mist or fog coming from the fridge.
This vapor belch is a normal part of the refrigeration cycle, and it indicates that the system is functioning as intended. However, if you notice any unusual or excessive vapor emissions, or if the fridge is not cooling properly, it might be a sign of a problem with the refrigeration system, and you should consider having it inspected by a qualified technician.