A modern kitchen is unthinkable without a reliable source of cold that keeps food fresh around the clock. Many take this unit for granted, thinking about its internal structure only at the moment of breakdown or high electricity bill. Understanding exactly how this complex machine functions helps extend its service life and avoid typical operating errors.
The work is based on the physical process of extracting heat from the internal chamber and releasing it into the environment. This is not the creation of cold “out of nothing”, but continuous thermal energy transfer using a special refrigerant. The cycle is repeated automatically until the thermostat registers the achievement of the set temperature.
The effectiveness of this process directly depends on the tightness of the circuit and the serviceability of the main components. If you know what forces your freezer to work, it will be easier to diagnose strange noises or lack of cooling. Let's take a look at the anatomy of this household giant.
Basic principle: heat selection
Fundamental physics says that heat spontaneously transfers from a hotter body to a colder one. The refrigerator's job is to do the opposite: take heat from food and release it into the room. To do this, the property of liquids to boil at low temperatures, if the pressure is lowered, and to condense when compressed is used.
The key element here is refrigerant (freon). This is a gas that circulates in a closed loop, constantly changing its state of aggregation. In the evaporator, which is located inside the freezer, it boils even at subzero temperatures, actively absorbing heat from the walls of the chamber.
After After the gas has absorbed heat, it heats up and expands. Next, he must give this energy out. That is why the back wall of the device is often warm - there is a condenser there, where the hot gas cools down and turns into liquid again, ready for a new cycle.
The heart of the system: the compressor and its role
The driving force of the entire process is compressor. This is an electromechanical pump that creates a pressure difference in the system. It compresses the refrigerant gas, increasing its temperature and pressure, and forces it through the condenser tubes. Without this unit, circulation is impossible.
Modern models can be equipped with inverter motors that operate smoothly, without turning off completely, but only changing power. Old models work on the “on-off” principle, which creates a characteristic click and vibration when starting. The service life of the compressor determines the overall service life of the equipment.
- 🔹 Piston compressors —classics of the genre, reliable, but noisy and vibrational.
- 🔹 Inverter models —quiet, economical, but sensitive to power surges in the network.
- 🔹 Linear compressors - often found in technology LG, have a minimum of moving parts.
If you hear a loud knocking or humming that does not stop, the compressor may be running in emergency mode or has lost oil. In some cases, it is necessary to replace the start relay, but most often the problem lies in the wear of the mechanical part of the motor.
Heat exchangers: evaporator and condenser
Heat exchange occurs in two main units: the evaporator (inside) and the condenser (outside). The evaporator consists of thin tubes or plates through which cold refrigerant flows. It is he who “freezes out” the camera. In systems No Frost the evaporator is hidden behind a plastic panel and is not visible to the eye.
The condenser is a grille on the back wall or built into the side walls of the case. Its task is to transfer heat to the air in the room as efficiently as possible. If this unit is contaminated with dust or animal hair, cooling efficiency decreases and energy consumption increases.
⚠️ Warning: Never block the ventilation openings or move the refrigerator close to the wall. A gap of 5-10 cm is necessary for free air circulation around the condenser.
It is important to keep the heat exchangers clean. The dust “felt” on the rear grille acts as a heat insulator, preventing the freon from cooling. In such a situation, the compressor will work without interruption, trying to reach the desired temperature, which will inevitably lead to its overheating and breakdown.
Defrost system: drip and No Frost
One of the main problems when cooling air is moisture. It condenses on cold surfaces and turns into ice. If the ice is not removed, it will block the access of cold to the food and cause the compressor to run idle. There are two main ways to combat this.
Drip system (or “crying evaporator”) is simple: the back wall of the main chamber periodically thaws itself when the compressor turns off. The water flows into the groove and goes through the drainage channel into a container above the motor, where it evaporates. The freezer requires manual defrosting.
System No Frost ("without frost") is more complex. Here the evaporator is located separately, usually behind the back wall of the freezer. The fan drives dry, cold air through the chambers. It turns on periodically Defrost heating element, which melts the ice on the hidden evaporator. Water also goes into the drainage.
Why does meat dry in No Frost?
In the No Frost system, the air constantly circulates and is very dry. This causes unsealed food to quickly dehydrate. Always use containers or film for storage.
Each system has its advantages. No Frost does not require defrosting, but it takes up useful space and is noisy due to the fan. The drip system is quieter and retains moisture better, but requires control over the ice crust in the freezer.
Refrigerant circulation diagram
To better understand the processes occurring inside, consider the freon path step by step. This is a closed cycle, the violation of which (leakage) stops the operation of the entire system. The pressure in different parts of the circuit differs significantly.
First, the compressor sucks cold low-pressure gas from the evaporator. It then compresses it, turning it into hot, high-pressure steam. This steam goes to the condenser, where it cools and becomes a liquid. Then, through the capillary tube (throttle), the liquid enters the evaporator, where the pressure drops sharply and it boils again.
| System unit | Refrigerant state | Temperature | Pressure |
|---|---|---|---|
| At the compressor outlet | Gas | High (+60...+80°C) | High |
| In the condenser | Liquid | Average (about room temperature) | High |
| After capillary tube | Steam + Liquid | Low (from -20°C) | Low |
| In the evaporator | Gas | Low (absorbs heat) | Low |
The capillary tube is a very thin copper coil that serves as a choke. It is this that divides the circuit into a high and low pressure zone. Its clogging or bending is a common cause of malfunctions, requiring the intervention of a specialist.
Electronics and temperature control
A modern refrigerator is a computer that controls temperature conditions. An electronic module that receives data from temperature sensors is responsible for everything. There are usually several of them: one in the chamber, one on the evaporator, sometimes there is a defrost sensor.
If the sensor “lies” and shows that the chamber is warmer than it actually is, the compressor will work non-stop, freezing the food. If the sensor shows that it is colder than reality, the equipment will be turned off, and the products will spoil.
☑️ Checking the electronics
In old models, mechanical control was responsible thermostat. This is a simple “box” with a bellows that reacted to the expansion of gas in the capillary. The mechanics are reliable, but less accurate and do not allow you to set the temperature with an accuracy of a degree.
⚠️ Attention: When diagnosing electronics, be sure to disconnect the device from the mains. A power surge or short circuit can damage an expensive control module.
Frequent problems and their causes
Knowledge of the device helps to understand the cause of the breakdown. If the refrigerator is humming but not cooling, there is most likely a problem with the compressor or a freon leak. If it freezes too much, the thermostat or sensor is to blame.
The appearance of a “coat” or ice in the main chamber (if it is not No Frost) may indicate a loose door fit or a malfunction of the defrost heating element. In No Frost systems, ice on food means that the water drainage channel is frozen or the fan is broken.
- 🔸 Continuous operation of the motor —refrigerant leak, door seal wear, capillary blockage.
- 🔸 Puddle under the refrigerator —the drainage channel is clogged or the food tray is cracked water.
- 🔸 Strong vibration - incorrect installation (legs not unscrewed), tubes touching the body.
Only simple steps are available to fix it yourself: defrosting, washing the drainage, replacing the light bulb. Repairing the circuit or replacing the compressor requires special equipment and skills.
Why does a refrigerator make gurgling sounds?
Gurgling is a normal sound of refrigerant moving through the pipes, especially in single-circuit models. The sound can also come from the drainage system when water flows there during defrosting. If the sound is not accompanied by a lack of cold, there is no need to worry.
Is it possible to install a refrigerator in an unheated dacha?
Most manufacturers do not recommend operation at temperatures below +10°C. The oil in the compressor thickens, making starting and lubrication difficult. In addition, in an unheated room, condensation may form on electronic boards.
How often do you need to defrost the refrigerator?
Full No Frost systems do not require defrosting at all; it is enough to wash the shelves once every six months. Drip systems need to be defrosted when the layer of ice in the freezer reaches 5-7 mm, usually 1-2 times a year.