A modern refrigerator is a complex engineering structure, where each element is made of a material selected taking into account its functional tasks and operating conditions. When choosing equipment, consumers often pay attention only to the design of the facade or the declared volume of the chambers, forgetting that it is the physical and chemical properties of the materials that determine the durability of the device, noise level and energy efficiency.
Understanding what exactly the unit is assembled from allows you not only to properly care for it, but also to avoid purchasing a model that will quickly lose its presentation or fail. In this article, we will analyze in detail the components of a refrigerator, from the outer casing to the microscopic pores in the insulation.
The quality of the alloys and polymers used directly affects the cost of the final product. Cheap models often skimp on metal thickness or use less durable dyes, which in the long run leads to corrosion or fading.
External body: steel, enamel or glass?
The basis of any refrigerator is its supporting frame, which is most often made of sheet metal. galvanized steel. This material was not chosen by chance: it has high mechanical strength, which allows it to withstand the weight of the compressor, filled shelves and products without deforming over time. Steel also perfectly shields electromagnetic radiation from a running motor.
To protect the metal from corrosion and give it an aesthetic appearance, the surface is coated with several layers of special powder paint or enamel. The polymerization process occurs at high temperatures, creating a monolithic film that is resistant to scratches and household chemicals. In the premium segment, glass is increasingly found, which require special care, but look impressive. stainless steel or glass, which require special care, but look impressive.
⚠️ Attention: When cleaning facades made of stainless steel or enameled metal, never use abrasive sponges or chlorine-containing products. This destroys the protective layer and provokes the appearance of microcracks, where rust later forms.
Glass panels, often used in designer series, undergo special hardening to increase strength. However, even tempered glass is afraid of pinpoint impacts from sharp objects. The metal case, in turn, can dent under a strong impact, but will remain sealed.
Inner chamber: plastic versus metal
The material of the internal surface of the refrigerator and freezer chambers is one of the main factors influencing hygiene and ease of use. The vast majority of modern models use food ABS plastic or its modifications with the addition of antibacterial components. This material is lightweight, does not corrode and is easy to clean.
However, plastic has its drawbacks: it is susceptible to mechanical damage and can absorb odors during prolonged contact with strong-smelling products. More expensive models can be equipped with an internal chamber made of stainless steel or food-coated aluminum. Metal chambers are much stronger, conduct cold better (which speeds up cooling) and do not absorb odors at all.
- 🧊 ABS plastic: cheap, lightweight, but scratched with a knife and turns yellow over time.
- 🛡️ Stainless steel: eternal, hygienic, but expensive and shows fingerprints.
- ❄️ Aluminium: excellent thermal conductivity, but requires a high-quality coating for food safety.
It is important to note that colored plastic inside the chamber (for example, blue or silver) is not just decoration. Often, silver ions or other antimicrobial additives are added to such compositions, which prevents the growth of bacteria on the walls.
Why does plastic crack in the cold?
Ordinary plastic becomes brittle at low temperatures. For freezers, special frost-resistant polymers are used that retain elasticity even at -24°C. Cheap plastic can burst from an accidental impact with a frozen product.
Thermal insulation: the secret of energy saving
Between the outer metal casing and the inner plastic chamber there is a space that is filled with heat-insulating material. Its quality directly determines how much electricity your refrigerator will consume and how quietly it will operate. The main material here is polyurethane foam (PPU).
This material foams directly in the enclosed space between the walls, creating a rigid structure with millions of microscopic cells filled with gas. It is these cells that effectively keep the cold inside, while not letting heat in from the outside. High-quality polyurethane foam also acts as a sound insulator, dampening vibrations of the compressor.
| Parameter | Polyurethane foam (PPU) | Polystyrene foam (old type) | Vacuum panels (VIP) |
|---|---|---|---|
| Thermal conductivity | Low (high efficiency) | Average | Very low (maximum) |
| Moisture resistance | High (does not absorb water) | Low (can accumulate moisture) | Absolute |
| Eco-friendly | Safe after hardening | Requires control | Safe |
| Cost | Average | Low | High |
In modern Eco-friendly models use foaming agents that do not destroy the ozone layer. The thickness of the insulation layer can vary, but in budget models it is often thinner, which makes the walls thinner but increases energy consumption.
Shelves and drawers: glass or lattice?
The internal filling of the refrigerator is under constant stress. Shelves must be able to withstand the weight of pots, bottles and grocery bags, as well as sudden temperature changes. The most popular and practical material for shelves today is tempered glass. It is stronger than usual, easy to clean and allows light (if there is a backlight) to evenly illuminate the lower tiers.
The freezer is traditionally equipped with shelves made of steel wire with anti-corrosion coating or grates. This is due to the fact that glass becomes more brittle at extremely low temperatures, while metal retains its properties. Boxes for vegetables and fruits are almost always made of transparent plastic, often using technology High Impact Polystyrenethat is resistant to impacts.
Glass shelves often have a plastic edge that prevents liquids from spilling to the lower levels and protects the end of the glass from chipping. It is important to monitor the integrity of this edging, since a damaged edge of the glass can become a point of destruction of the entire shelf.
⚠️ Attention: Never place hot dishes on a glass shelf, even if it is tempered. Sudden temperature changes can cause thermal shock and glass breakage. Allow the food to cool to room temperature.
Seals and tightness
The key element that ensures the operation of the refrigerator is the door seal. It prevents warm air from getting in and cold air coming out. They are made from special rubber or a thermoplastic elastomer composition, which remains elastic over a wide range of temperatures.
Inside the rubber profile there is often a magnetic tape that ensures a tight fit of the door to the body around the entire perimeter. The quality of the rubber determines how long the seal will retain its shape. Over time, cheap materials become tanned, crack and stop sealing the chamber, which leads to ice freezing and excessive energy consumption.
- 🔍 Visual inspection: rubber should be smooth, without cracks or creases.
- 🧲 Magnetic test: the door should close with a slight bang and hold tightly.
- 🧼 Care: Rubber seals should be wiped with a soft damp cloth, avoiding aggressive chemicals.
Modern seals often have an antibacterial coating that prevents mold from forming in the folds of the material, which is especially important for refrigerators with high humidity inside.
☑️ Checking the condition of the seal
Tubes and heat exchangers: copper or aluminum?
In the “heart” of the refrigerator, in the hidden refrigerant circulation system, metals with high thermal conductivity are used. The traditional material for evaporators and condensers was copper. It is not subject to corrosion, is easy to solder and conducts heat well. However, copper is expensive, so manufacturers are increasingly switching to aluminum or steel.
Aluminum tubes are lighter and cheaper, but they are more susceptible to mechanical damage and corrosion, especially if there are microscopic leaks or impurities in the system. Steel tubes (aluminum steel) combine the strength of steel and the anti-corrosion properties of aluminum, but they are more difficult to repair.
The choice of heat exchanger material affects the maintainability of the unit. The copper circuit can be soldered in case of leakage in almost any workshop. Not all services work with aluminum or steel, since special equipment and fluxes are required.
Frequently asked questions (FAQ)
Is it possible to wash the interior walls of the refrigerator with hot water?
The use of boiling water or very hot water (>60°C) is not recommended, especially for plastic chambers. The plastic can be deformed, and temperature changes will lead to the formation of condensation and stress on the structure. It is better to use water at room temperature or slightly warm with the addition of a mild detergent.
Why does the back wall inside the refrigerator sometimes become covered with ice?
This is normal for refrigerators with drip system defrosting. Moisture from the air condenses on the cold back wall (where the hidden evaporator is located), freezes, and then flows down into the drain hole when the compressor is turned off. If there is too much ice, check the door seal.
Is polyurethane foam inside the walls harmful to health?
In the frozen state, polyurethane foam is absolutely inert and safe for health. It is securely sealed between a metal body and internal plastic. Only the combustion process of the material can pose a danger, so old refrigerators should not be burned or exposed to open fire when disposing of them.
What is the best way to wipe glass shelves to avoid streaks?
For glass shelves, alcohol-based window cleaners or a solution of water and vinegar (1:1 ratio) are best suited. Use soft microfiber, which does not leave lint and effectively removes greasy stains without streaks.