When you buy a new household appliance, you first pay attention to its design, capacity and energy efficiency. However, few people think about what is hidden behind the glossy doors and what exactly allows them to keep food fresh for weeks. Understanding what a refrigerator is made ofhelps not only to choose a high-quality model, but also to properly care for it in the future.
A modern refrigerator is a complex engineering complex consisting of dozens of components, each of which performs a strictly defined function. The materials used in production undergo strict control, since they come into contact with food and are under pressure. In this article, we will analyze the design of the unit in detail so that you know what exactly is working in your kitchen.
Metal frame and outer casing
The basis of any refrigeration unit is a durable metal casing, which serves as the skeleton of the entire structure. Most often for its production it is used sheet steel, which has undergone special treatment to protect against corrosion. It is steel that provides the rigidity necessary to hold heavy shelves, a compressor and an insulating layer.
The external surface is covered with a polymer layer or enamel, which gives the device an aesthetic appearance and additional protection. Expensive class models Stainless Steel or Inox use stainless steel, which looks premium, but requires special care. More budget options are often powder coated, which is scratch-resistant.
The rear wall of the case is also made of metal, but often has perforations or fins to better dissipate heat from the condenser. It is important to understand that any mechanical damage to the outer layer can lead to accelerated rusting, so protect the case from impacts.
⚠️ Attention: Never try to drill holes in a metal case yourself to lay wires or fasteners - you can damage hidden refrigerant pipes or break the seal of the insulation.
The quality of the metal directly affects the noise level: thin sheets can resonate and hum when the compressor is running, while thicker steel dampens vibrations. Manufacturers are increasingly using composite materials in combination with metal to reduce weight without losing strength.
Internal materials: plastic and glass
The interior of a refrigerator is an area where completely different requirements for materials apply. Here, food contact safety and hygiene play a major role. The main material for the manufacture of internal walls and drawers is ABS plastic (acrylonitrile butadiene styrene).
This material was not chosen by chance: it is impact-resistant, does not absorb odors and is easy to clean. Unlike old polystyrene, modern ABS plastic is more resistant to low temperatures and does not crack under sudden changes. It is from this that popular systems are made No Frost i Multi Air Flow, since plastic allows you to create complex shapes of air ducts.
Shelves are most often made of tempered glass, which can withstand significant loads. The glass is coated with a special compound that prevents the dishes from slipping. Some manufacturers are experimenting with antibacterial additives in plastic, which is especially important for meat and fish storage areas.
Particular attention should be paid to door seals. They are made of special rubber with magnetic tape inside. This material must remain elastic for years, not harden in the cold and fit tightly to the body, ensuring tightness.
Thermal insulation: the heart of energy efficiency
The most important component that determines how well the refrigerator keeps the cold is the thermal insulation layer. It is located between the outer metal casing and the inner plastic chamber. 99% of modern models use polyurethane foam (PPU).
This material is pumped in liquid form into the space between the walls, where it foams and hardens, forming a monolithic structure without seams. Polyurethane foam has excellent heat-insulating properties and high adhesion to metal. The thickness of the layer can vary from 3 to 6 cm depending on the energy efficiency class of the model.
Previously, freon in solid form or glass wool was used as an insulator, but modern environmental and efficiency standards require the use of polyurethane foam. It is high-quality insulation that allows the refrigerator to consume a minimum of electricity, maintaining a stable temperature.
Why can’t you cut off the foam during repairs?
Polyurethane foam in modern refrigerators serves not only as insulation, but also as a structural element (load-bearing element). Its removal can lead to deformation of the body and disruption of the door geometry, which will make it impossible to close tightly.
It is important to note that damage to the insulating layer (for example, due to deep corrosion of the body) leads to a sharp increase in energy consumption and the formation of condensation inside the walls, which accelerates the destruction of the metal.
Refrigerants and cooling system
The life cycle of cold begins with a refrigerant - a substance that circulates in a closed circuit, taking heat from the chamber and releasing it into the environment. Previously, freons were widely used, which destroy the ozone layer, but today the industry has switched to safer analogues.
Modern refrigerators are filled with refrigerants of the brand R600a (isobutane) or R134a. Isobutane is considered the most environmentally friendly and efficient, it is non-toxic and has excellent refrigeration properties. However, it is fire hazardous in high concentrations, which requires special tightness of the system.
The tube system through which the gas moves is made of aluminum or copper. Copper has better thermal conductivity and ductility, but it is more expensive. Aluminum is cheaper, but is more susceptible to corrosion and is more difficult to solder. In budget models you can often find combined aluminum-steel systems.
| Refrigerant type | Environmental friendliness | Efficiency | Safety |
|---|---|---|---|
| R600a (Isobutane) | High | Very high | Fire hazard |
| R134a | Average | High | Safe |
| R12 (Obsolete) | Low | Medium | Safe |
| R290 (Propane) | High | High | Fire hazard |
The amount of refrigerant in the system is strictly regulated by the manufacturer and is indicated on a special label. Independent refilling or replacement of gas requires professional equipment and skills.
Compressor: the engine of your refrigerator
The heart of any refrigerator is the compressor - a device that compresses the refrigerant and forces it to circulate through the system. The service life of the entire device depends on the quality of this unit. Most modern models are equipped with piston compressors.
The principle of their operation is similar to an internal combustion engine: the piston moves inside the cylinder, compressing the gas. The compressor housing is sealed and filled with oil to lubricate the rubbing parts. In recent years, inverter models have been gaining popularity, which are quieter and more economical than conventional ones.
The materials used inside the compressor must withstand enormous loads and high temperatures. The shafts are made of high-strength steel, and the electric motor windings are coated with heat-resistant varnish. The reliability of the compressor is the main factor influencing the manufacturer's warranty.
The noise when the refrigerator operates comes from the compressor. High-quality motor suspension inside the casing and the use of rubber shock absorbers help minimize vibrations transmitted to the body.
Electronics and control systems
A modern refrigerator is no longer just a metal box with a motor, but a smart device controlled by electronics. It is responsible for all processes electronic control module, which receives signals from temperature and humidity sensors.
Sensors (thermistors) are located in different areas: in the freezer compartment, in the refrigerator compartment, on the evaporator. They are made of materials that change their resistance depending on temperature. This allows the system to precisely regulate the operation of the compressor and fans.
In models with the function Smart Wi-Fi modules, cameras and additional sensors are added. Control boards are protected from moisture and condensation with special varnishes, but still remain a vulnerable point during power surges in the network.
⚠️ Attention: Electronic control boards are extremely sensitive to voltage surges. To protect an expensive refrigerator, it is strongly recommended to use a voltage stabilizer or surge protector of good quality.
The control system also uses relays that click when the compressor is turned on and off. This is a normal operating situation, indicating the correct operation of the automation.
Environmental friendliness and recycling of materials
The question of what the refrigerator is made of is inextricably linked with the problem of its disposal. The device consists of materials that can and should be recycled. The metal body makes up the bulk and is sent for remelting.
The plastic of the internal chambers is also recyclable, but it is often separated from the metal. The most complex component is polyurethane foam, which in older models could contain harmful substances. Modern factories are equipped with installations for the safe disposal of insulation.
Refrigerants must be pumped out with professional equipment before disposing of the casing. The release of freon or isobutane into the atmosphere is prohibited by law in many countries due to their impact on the climate.
☑️ What to check before disposing of an old refrigerator
By purchasing equipment from responsible manufacturers, you support technologies aimed at reducing harm to the environment at all stages of the product life cycle.
Often asked questions (FAQ)
Is it possible to paint the interior plastic of a refrigerator?
It is strictly not recommended. Conventional paints are toxic and are not intended for food contact at low temperatures. They can crack and peel if they get into your food. In addition, solvents can corrode the plastic.
Why is the back wall inside the refrigerator covered with ice?
In systems Direct Cool (drip system) this is a normal operating process. Moisture condenses on the cold evaporator, freezes, and then, when the compressor is turned off, melts and flows into the drain. In systems No Frost there should be no ice inside.
What are the tubes inside made of and can they burst?
The tubes are made of aluminum or steel. They can burst only due to mechanical damage (a blow with a knife during defrosting, an attempt to pick out ice) or due to through corrosion on the outside. During normal operation, they last for decades.
Is R600a gas safe in everyday life?
Yes, it is safe. Although isobutane is flammable, its amount in the system (about 50-60 grams) is too small to create an explosive concentration in the room, even with complete depressurization. The gas concentration instantly dissipates.