A modern refrigerator is one of the most complex household appliances in the house, ensuring the safety of food by maintaining low temperatures. The internal structure of this unit is a closed thermodynamic system, where each element plays a critical role. Understanding what refrigerators are made of is necessary not only for engineers, but also for ordinary users who want to extend the life of their equipment and choose a new model wisely.
The design of any refrigeration unit is based on the principle of refrigerant circulation, which transfers heat from the internal chamber to the external environment. Despite the variety of designs, brands and additional functions, the basic architecture remains unchanged for decades. The main components are hidden from the user's eyes, located in the technical compartment or behind decorative panels, but it is their quality that determines the efficiency of the entire device.
In this article we will analyze in detail each component, starting from the heart of the system - the compressor, and ending with complex control electronics. You will learn how various metals, gases and electrical circuits interact with each other, turning an ordinary outlet into a source of cold.
Heart of the system: compressor and motor-compressor unit
The main engine of any refrigerator is the compressor, which is often called its “heart”. It is this unit that is responsible for compressing and pumping the refrigerant through the closed circuit of the system. Modern models most often use hermetic piston or inverter compressors, which differ in noise level and energy efficiency. Motor-compressor creates the necessary pressure, thanks to which the refrigerant can change its state of aggregation, absorbing and releasing heat.
Traditional piston models work cyclically: they turn on at full power, cool the chamber to the set temperature and turn off. Inverter analogues, such as popular models from Lg or Samsung, are able to smoothly regulate the speed of rotation of the motor shaft. This allows you to avoid sudden power surges and maintain the temperature more stable, which is especially important for storing sensitive products.
⚠️ Attention: Replacing the compressor requires professional soldering of the tubes and vacuuming of the system. Independent repair of this unit without special equipment is impossible and dangerous.
The compressor housing is usually made of steel and painted black for better heat dissipation. Inside there is an electric motor and a pump part immersed in oil. Oil is necessary to lubricate rubbing parts and seal the gaps between the piston and cylinder. The reliability of this unit directly affects how many years your unit will last. constantly) unit.
Heat exchange elements: condenser and evaporator
If the compressor creates pressure, then the heat exchangers are responsible for the direct cooling process. The system consists of two main radiators: a condenser and an evaporator. The condenser is usually located on the back wall of the refrigerator (black grille) or built into the side walls of the case. Here, hot gaseous freon gives off heat to the environment and turns into a liquid state.
The evaporator, on the contrary, is located inside the refrigerator or freezer, often hidden behind a plastic panel. Passing through the thin tubes of the evaporator, the liquid refrigerant boils under low pressure and turns into gas, actively absorbing heat from the internal volume of the chamber. The materials from which these elements are composed are usually aluminum or steel with copper inserts, which provides high thermal conductivity.
Models with the system No Frost use one common evaporator located in a hidden compartment, usually at the top of the freezer or between the chambers. Air is driven through it by a fan and distributed throughout the entire volume. This prevents the formation of an ice crust on the products, but adds additional mechanical elements to the design.
Refrigerant: the working fluid of the refrigeration machine
The substance that circulates inside the tubes is called refrigerant or freon. It is a gas with special thermodynamic properties, allowing it to easily transition from liquid to gaseous state and back when pressure changes. Previously, R12 freons were widely used, which turned out to be harmful to the ozone layer, so modern refrigerators are filled with more environmentally friendly gases, such as R134a or R600a (isobutane).
Isobutane, used in many modern models, is explosive in high concentrations, so special attention is paid to tightness during production connections. The amount of refrigerant is strictly regulated by the manufacturer and is indicated on the technical sticker. A lack or excess of gas leads to incorrect operation: the compressor may overheat, and the temperature in the chambers will not drop to the required values.
Refrigerant circulation occurs in a closed circuit. It is important to understand that freon is not consumed during operation, like fuel in a car. If the refrigerator stops freezing, this almost always means a violation tightness of the circuit and a gas leak, and not its “production”.
Why can’t you mix different types of freon?
Mixing different brands of refrigerants (for example, R134a and R600a) leads to a chemical reaction, the formation of acids and complete failure of the compressor. The system requires a complete flush when changing the type of gas.
Defrosting and temperature control system
In refrigerators with an automatic defrosting system (No Frost or drip system), heating elements (tubular electric heaters) and sensors play a critical role. Heating elements are a nichrome spiral in a metal shell, which heats up at the command of the control unit. Their task is to melt the frost that has accumulated on the evaporator during operation.
The process is controlled by an electronic module that reads readings from various sensors. The defrost sensor records the temperature of the evaporator in order to turn off the heating element when the ice melts, but not to overheat the plastic. The temperature sensor in the chamber tells the controller when to start the compressor. In older models, this function was performed by a mechanical thermostat with a bellows filled with gas or liquid.
Inside the chamber or on the body
In the technical compartment
| Component | Function | Location |
|---|---|---|
| Defrost heating element | Heating and melting ice on the evaporator | Near the evaporator (hidden). data-i="100">Timer (in older models) |
| Defrost sensor | Evaporator temperature control | On the surface of the evaporator |
| Thermostat | Turning the compressor on/off | |
| Timer (in older models) | Switching cold/defrost modes |
The control unit, or the “brain” of the refrigerator, analyzes all incoming signals and makes decisions. In modern models, this is a complex board with a microprocessor that can diagnose faults and display error codes on the display. In simple models, this is a set of electromechanical relays.
☑️ Signs of a malfunction of the defrost system
Insulation and body elements
To prevent the cold from escaping outside and the heat from the kitchen not penetrating inside, the refrigerator body is a kind of thermos. Between the inner plastic container and the outer metal casing there is a layer of thermal insulation. Most often, polyurethane foamis used for these purposes, which is pumped in liquid form and, when solidified, forms a monolithic porous structure with excellent heat-insulating properties.
The quality of foaming directly affects energy consumption. If the insulation is defective or damaged during transportation, “cold bridges” may appear on the outer walls—areas that will freeze or, conversely, become very hot. The interior of the chambers is made of impact-resistant polystyrene or ABS plastic, which is resistant to low temperatures and food acids.
⚠️ Attention: When cleaning the refrigerator, do not use abrasive sponges or aggressive solvents for plastic, as they can damage the structure of the polymer and it will become brittle.
Doors refrigerators also have a multi-layer design with insulation inside. A magnetic seal is installed around the perimeter of the doorway. It is made of elastic rubber with a magnetic cord embedded inside. The task of the seal is to ensure a tight fit of the door to the body, preventing warm air from getting inside when closed.
Additional components and electrical circuit
In addition to the main systems, the refrigerator consists of many auxiliary elements. No Frost models must have fans that provide forced air circulation. They can be installed in the freezer compartment or in the channel between the chambers. Failure of the fan results in severe frost in one part of the refrigerator and heat in the other.
The electrical circuit includes a start-up relay that starts the compressor motor and protects it from overloads. In inverter models, this function is performed by a complex frequency converter. The circuit also contains lighting lamps, control buttons and, in some models, valves for switching air flows for the “Fresh Zone”.
Understanding the device helps not only in repair, but also in proper operation. For example, knowing where the condenser is located allows you not to place the refrigerator close to the wall, and understanding the operation of heating elements explains why sometimes the outside of the case can be warm - this is a normal process of heat removal or operation of the defrost system.
Frequently asked questions (FAQ)
Why does the refrigerator hum or make strange sounds?
The noise can come from vibration of the compressor, fan operation, or gurgling of refrigerant in the pipes. If the sound changes abruptly (a knocking or grinding sound appears), this may indicate wear on the compressor bearings or a foreign object getting under the fan.
Is it possible to transport the refrigerator lying down?
It is strictly not recommended. When transported lying down, oil from the compressor may leak into the refrigerant circuit, which will lead to clogging of the capillary tube and damage to the unit. There is also a risk of the internal tubes being torn off due to vibration.
How often do you need to defrost a No Frost refrigerator?
The No Frost system does not require manual defrosting to remove ice, as this happens automatically. However, it is recommended to completely turn off the appliance 1-2 times a year, wash it and let it dry for hygiene and check the seals.
What to do if water appears inside the refrigerator?
Most often this indicates a clogged drain hole through which condensate should drain into a container above the compressor. It is necessary to clean the hole with soft wire or a brush. Also, the reason may be that the door is not tightly closed.
How long does a modern refrigerator last on average?
The service life depends on the build quality and operating conditions. On average, modern models are designed for 7-10 years of active work. Key components, such as the compressor, can last longer, but electronics and seals often require attention earlier.