A modern refrigerator is a complex engineering structure that keeps your food fresh every day, but few people think about what materials are hidden behind the glossy facade. If you ask the average person what a refrigerator is made of, the answer will most likely be “metal and plastic,” but the real picture is much more interesting and technologically advanced. Inside the case lies a multilayer structure, where each component performs a strictly defined function: from thermal insulation to refrigerant circulation.
Understanding your household appliance is necessary not only for general development, but also for competent operation. Knowledge of materials helps to properly care for the surface, avoid damage during cleaning and quickly diagnose breakdowns. For example, understanding the structure of the internal coating will tell you why you can’t use abrasive sponges, and knowledge of the structure of the compressor will explain why it is important to maintain the installation level. what it consists of your household appliance is necessary not only for general development, but also for proper operation. Knowledge of materials helps to properly care for the surface, avoid damage during cleaning and quickly diagnose breakdowns. For example, understanding the structure of the internal coating will tell you why abrasive sponges should not be used, and knowledge of the structure of the compressor will explain why it is important to maintain the level of installation.
In this article we will analyze in detail the design of modern refrigeration equipment, consider the chemical composition of insulation, types of metals and features of polymers. You will find out why the walls seem thin but hold the cold well, and what rare metals are used in the control electronics. This will allow you to look at kitchen appliances completely differently.
External casing and decorative coating
The first thing we see is the outer perimeter of the device. Traditionally, the basis for the manufacture of the case is sheet steel, which goes through a stamping process. The metal is chosen with a thickness of 0.5 to 0.8 mm, which ensures the necessary structural rigidity with minimal weight. Steel is coated with special compounds to protect against corrosion, since the kitchen is a place with high humidity and temperature changes.
The decorative layer can be made in the form of enamel paint, powder coating or laminated film. Premium models often use Fingerprint Free anti-corrosion coating, which repels fingerprints. Some manufacturers are experimenting with glass and tempered polymer, creating mirror surfaces that visually expand the space. stainless steel with Fingerprint Free anti-corrosion coating that repels fingerprints. Some manufacturers are experimenting with glass and tempered polymer, creating mirrored surfaces that visually expand the space.
⚠️ Attention: When cleaning a steel case, it is strictly forbidden to use chlorine-containing products and hard brushes. Aggressive chemistry can damage the protective varnish layer, which will lead to the appearance of microcracks and subsequent corrosion of the metal.
An important element of the external part is door handle. In budget segments, it is made of durable ABS plastic, which is easy to mold and pleasant to the touch. In more expensive models you can find aluminum alloys or even chrome-plated brass. Handle fastening also varies: from hidden screws to Push-to-open systems, where mechanical elements are replaced with magnetic latches.
Internal chamber and shelf materials
Looking inside, we see the space that is in direct contact with the products. Here the requirements for materials change dramatically: they must be food-grade, safe and easy to clean. The main material for the internal lining is ABS plastic (acrylonitrile butadiene styrene). This is an impact-resistant polymer that does not crack at low temperatures and can withstand accidental impacts from jars or pans.
In some models, especially in the freezer area, polystyrene can be used, but it is less resistant to mechanical stress. The current trend is the use of antibacterial additives in plastic, which suppress the growth of bacteria on the surface. Shelves are most often made of tempered glass, capable of supporting weights of up to 50-80 kg, which allows you to store heavy workpieces in jars without the risk of collapse.
Door shelves and vegetable drawers are also made of transparent plastic. For boxes, material with increased elasticity is often used so that it does not break when fully loaded with heavy vegetables. Seals On the doors, which we will talk about below, they are inserted into special grooves in the plastic door profile, creating a single sealed system.
Thermal insulation: secrets of preservation cold
The most important part of the structure, hidden from the user’s eyes, is the thermal insulation layer. It is he who is responsible for ensuring that the cold remains inside and the heat from the kitchen does not penetrate to the food. Between the outer metal casing and the inner plastic box (PPU) is pumped. This material is foamed directly in the factory, filling all voids and creating a monolithic layer without seams or cold bridges. polyurethane foam (PPU). This material is foamed directly in the factory, filling all voids and creating a monolithic layer without seams or cold bridges.
Polyurethane foam consists of two components that, when mixed, react and harden, forming a structure of millions of microscopic cells filled with gas. It is the gas enclosed in these cells that has low thermal conductivity. Modern refrigerators use polyurethane foam with cyclopentane, which is environmentally safer than old freon-containing analogues.
| Characteristics | Description of material | Impact on operation |
|---|---|---|
| Thermal conductivity | Low (0.022 W/m K) | Minimizes cold loss |
| Density | 35-45 kg/m³ | Ensures structural rigidity |
| Moisture absorption | Minimal | Prevents mold formation |
| Elasticity | High | Compensates vibrations compressor |
The thickness of the insulation layer directly affects the energy efficiency of the class A++ or A+++. The better and thicker the layer of polyurethane foam, the less often the compressor turns on to maintain the set temperature. Manufacturers are constantly improving the PU foam formula, adding graphite nanoparticles to improve the reflection of thermal radiation.
Why do the walls of the refrigerator sometimes get hot?
The side walls can heat up due to the operation of the condenser, which often built into the side panels. This is normal: the metal gives off heat, and the thick layer of insulation inside prevents it from penetrating the food.
Cooling system and refrigerants
The heart of any refrigerator is the compressor-condenser unit. The compressor, located at the lower rear, is a sealed pump motor. Inside its body there are electric motor a mechanical part immersed in a special oil. The compressor shell is made of durable steel that can withstand high pressure and vibration.
Refrigerant circulates through a system of tubes - a substance that takes heat from the chamber and releases it to the environment. Modern models use environmentally friendly gases, such as isobutane (R600a). It does not destroy the ozone layer and has excellent refrigeration properties. Copper or aluminum evaporator tubes can be built into the walls of the housing (hidden evaporator) or located openly in the freezer.
⚠️ Attention: Never try to defrost the freezer with a knife or sharp objects. You risk puncturing the thin-walled evaporator tube. A refrigerant leak will lead to failure of the refrigerator and will require expensive repairs with sealing and refilling.
In models with the system No Frost fans and additional heating elements (heating elements) are added. Fans drive air through the evaporator, evenly distributing the cold, and heating elements are periodically turned on to thaw ice on the evaporator. All these elements are controlled by an electronic module that reads temperature sensors.
Electronics and control system
A modern refrigerator is a computer that can cool. The entire process is monitored by an electronic control unit, usually located in the upper part of the case or behind the decorative panel. It includes a printed circuit board with microprocessorcapacitors and relays. It is the “brain” of the device that makes the decision to turn on the compressor, based on data from the thermostats.
Temperature sensors (thermistors) are located in different zones: in the refrigerator, freezer, and on the evaporator. They are small elements whose resistance varies depending on the temperature of the environment. Advanced models may have door opening sensors, humidity sensors for the freshness zone, and even Wi-Fi modules for remote control.
☑️ Electronics diagnostics
The user interface can be mechanical (control with divisions) or electronic (display and touch buttons). Electronic panels allow you to accurately set the temperature in 1-degree increments and activate special modes, for example, “Vacation” or “Super Freeze”. The reliability of electronics depends on the quality of soldering and protection from power surges.
Seals and fittings
The tightness of the refrigeration chamber is the key to its efficient operation. Door seals made of soft rubber or thermoplastic elastomer are responsible for this. Inside the rubber profile there is often a magnetic tape, which ensures a tight fit of the door to the metal body around the entire perimeter. The shape of the seal (profile) is developed by engineers so that when closing, an air cushion is created.
Fittings include door hinges, opening limiters and a plinth grille. The hinges are made of steel with a zinc coating to protect against rust. In some models, the hinges are equipped with closers that close the door smoothly and silently even with a slight push. The base grille at the bottom not only hides the compressor and wiring, but also directs air flows to cool the unit.
Particular attention should be paid to materials in contact with water in dispenser or generator systems ice. Food grade silicones and plastics that do not emit harmful substances during prolonged contact with liquid are used here. Water filters, if included in the design, contain activated carbon and ion exchange resins.
Why are some refrigerator parts made of copper and others made of aluminum?
Copper has better thermal conductivity and is easier to solder, so it is often used in critical heat exchange units and in older models. Aluminum is cheaper and lighter, so in modern budget and mid-range models, evaporators and condensers are often made of aluminum or its alloys (Almec), coated with special anti-corrosion compounds.
Is it possible to recycle a refrigerator after the end of its service life?
Yes, the refrigerator consists of recyclable materials: steel, copper, aluminum, plastic and glass. However, it must be disposed of through special collection points, since it contains refrigerant and insulation inside, which can be harmful to the environment if destroyed incorrectly.
Does the color of the body affect the operation of the refrigerator?
Technically, the color does not affect the cooling of the products inside, since the chamber is insulated. However, dark cabinets (black, graphite) heat up more from direct sunlight outside, which may cause the compressor to work a little harder if the refrigerator is standing in the sun. Light surfaces better reflect external heat.
What is the “new refrigerator” smell made of and how to get rid of it?
The characteristic smell comes from new polymers (plastic, rubber seals, glue) used during assembly. This is normal and safe. To get rid of the smell, just wipe the chamber with a solution of water and vinegar or soda and leave the refrigerator open for several hours with the fan on.