1. What makes a refrigerator cold?
First of all, it is necessary to understand the simple facts:
- The refrigerator removes heat from the objects that are inside it and does not purposefully cool the products.
- Heat spreads from warm to colder objects. The higher the temperature difference of the objects, the faster the heat moves, and this happens until the temperature becomes the same everywhere.
But as the air warms up, in turn, it needs to be cooled somewhere.
When warm products are placed in the refrigerator, thermal energy leaves them in the ambient air of the freezer or cooling compartment. The contents are cooled as a result. To cool the heated air and replace it near refrigerated products, the correct organization of airflows is important. Air movement is provided by ventilation. Air goes through an evaporator equipped with a fan. There, heat is transferred to the refrigerant (usually gas freon) quickly, because the temperature difference is large. Freon temperature is quite low – from 14ºF to -40ºF. In classic refrigerators, the refrigerant flows through the channels in the walls of the freezer and radiators that protrude into the main chamber. They are placed on top so that the heavier cold air goes down by gravity.
2. How do a fridge and freezer work?
The main components of a fridge are a compressor (motor) and an evaporator. When the motor starts, freon moves through the tubes of the system, providing cooling the chambers. Freon passes into the evaporator, boils, absorbs heat and goes into a vaporous state. The engine compresses freon and creates pressure for its distillation through the system. Once in the condenser, the refrigerant cools (the heat goes out), turning into a liquid. The condenser gives to the environment the heat generated by the compressor during operation. So the refrigerator does not overheat. To set the desired temperature in the chambers, a thermostat is installed. Passing to the filter drier, the refrigerant gets rid of moisture. The motor drives freon and repeats the cycle until the optimum temperature is established in the compartment.
Since the refrigerator has zones with zero temperature, freon is cooled in the freezer to a certain level, and then moves to the upper compartment. As soon as the indicators reach the norm, the thermostat is activated, and the start relay turns off the motor.
The evaporator is located in the freezer compartment. The cold that it produces is distributed through the cooling compartment by a fan. In the chamber at the level of the shelves, there are openings where the cold stream exits and is evenly distributed throughout the compartment.
When you open the refrigerator door, a lot of warm and moist air enters inside. The evaporator is very cold, and the water immediately condenses on its surface, covering it with hoarfrost, and then with a thicker layer of frozen ice. Ice interferes with heat transfer between air and freon. The efficiency of the refrigerator decreases, it consumes more electricity and wears out more. To prevent this, you need to defrost the refrigerator from time to time.
Modern systems are defrosted by a timer – after 6-12 hours, air cooling stops, the ice melts for a few minutes, and the surface of the evaporator is freed from it. Sophisticated electronics or a manual timer regularly stops the compressor and starts a defrost (electric heater), which heats the evaporator. Flowing water is collected in a pan through drainage holes, from where it evaporates. To protect the cooling circuit from overheating during defrosting, a thermostat is used. It opens the circuit when a certain temperature is reached.
Chilled products produce less heat, air remains cold for a long time. The thermostat controls the process by turning the compressor on and off based on the thermometer. The working temperature range is adjusted with the knob, usually, there are gaps of several degrees.
As a rule, in the refrigerator there is only one evaporator; it supplies cold air everywhere – to the freezer and the main compartment. To maintain a lower temperature in the freezer, the cooled air is predominantly located in it, only a small amount of it enters other compartments. The air balance between the freezer and the main compartment is controlled by a damper. It is located in the channel connecting the compartments and is operated by a separate controller.
3. Do fridges need to be Regassed?
No, they don’t. When your fridge is working properly, you don’t need to regas it.
Filling freon in the refrigerator is a common service that is required when you faced the need to repair the refrigerator. Basically, this is one of the stages of the overhaul of the refrigerator. But the main reason is the leak of freon. It is important to know that freon is colorless and odorless! Therefore, “feel” that freon is leaving the system is impossible. Symptoms of freon leakage include the following:
- the refrigerator does not cool the food sufficiently while the freezer is working normally;
- the refrigerator starts to freeze worse;
- the refrigerator stops working;
- local uneven freezing of the snow coat occurs;
If you have any of the symptoms, you should address a professional. If freon has left the system, it is necessary to determine and eliminate the leakage by repairing or changing the evaporator.
Now you understand how the refrigerator works and how it should work to extend the useful life of the device and its proper operation.