Internal structure of the refrigerator: diagram, principle of operation and hidden parts

When you open the refrigerator door to take out food, you hardly think about what is hidden behind the plastic panels and metal walls. Meanwhile, the internal structure of this household appliance is a complex system, where each element performs a strictly defined function. From compressor, which works as the “heart” of the unit, to evaporator, which is responsible for cooling, all parts interact with each other, maintaining the optimal temperature for storing food.

In this article we will look at how the refrigerator works from the inside, what technologies are used in modern models (for example No Frost or Low Frost), and what can go wrong if one of the components fails. You will learn where capacitoris, why ice forms in the freezer, and how to check the functionality of the thermostat without calling a technician. The information will be useful both to those who are planning do-it-yourself repairand to those who simply want to better understand how the equipment works in their home.

We will pay special attention hidden details that are not written about in the instructions - for example, how it works defrosting system in models with Full No Frost, or why some refrigerators Samsung i LG use two compressors instead of one. We will also figure out what materials are used for thermal insulation and why this is important for energy efficiency.

1. The main components of the refrigerator: what is hidden behind the walls

Any refrigerator, regardless of the brand (Atlant, Indesit, Beko or Liebherr), consists of several key components. They can be divided into two groups: refrigeration circuit (responsible for refrigerant circulation) and electronic/mechanical part (control and monitoring). Let's look at each element in more detail.

The first and most noticeable component is compressor. This is an electric motor with a piston system that compresses the refrigerant (usually isobutane or freon R600a) and forces it to circulate through the tubes. In modern models, the compressor is often hidden in the lower part of the housing and can be linear (classic) or inverter (more economical and quiet). For example, refrigerators Samsung RB30A3200SA use an inverter compressor Digital Inverter Technologywhich automatically adjusts the power depending on the load.

Next comes condenser a coil (usually located on the back wall), where the hot refrigerant is cooled and passes from a gaseous state to a liquid. In models with the No Frost system, the capacitor can be hidden inside the case to improve the design. Important: if the condenser is contaminated with dust, the refrigerator begins to overheat and consume more electricity.

Completes the circuit evaporator - the part where the refrigerant evaporates, absorbing heat from the chamber. In conventional refrigerators, the evaporator is located in the freezer (hence the ice and frost), but in systems No Frost it is hidden behind the panel, and moisture is removed automatically using a fan.

• 🔧 Compressor is the “heart” of the refrigerator, responsible for the circulation of the refrigerant. It can be linear or inverter.
• 🌀 Condenser - cools the refrigerant, usually located on the rear wall. Requires regular cleaning.
• ❄️ Evaporator - absorbs heat, in systems No Frost hidden behind the panel.
• 📊 Thermostat/thermostat - controls the temperature, if the refrigerator breaks down, it may not work turn off.
• ⚡ Start relay —starts the compressor, a common cause of malfunctions during power surges.

⚠️ Attention: In refrigerators with a system No Frost The evaporator may freeze if the defrost heater breaks down. If ice appears in the freezer and the fan does not work, this is a reason to check the defrosting heating element.

2. Operating principle: how a refrigerator maintains cold

The operation of a refrigerator is based on Carnot cycle a physical process in which the refrigerant sequentially changes its state (gas → liquid → gas), removing heat from the chamber. The cycle consists of four stages:

1. Compression: The compressor compresses the refrigerant (gas), increasing its temperature and pressure.
2. Condensation: Hot gas passes through the condenser, gives off heat to the environment and becomes liquid.
3. Expansion: Liquid refrigerant enters the capillary tube (or thermostatic valve in modern models), where its pressure drops sharply.
4. Evaporation: The refrigerant enters the evaporator, boils, absorbing heat from the fridge compartment, and turns back into gas.

This cycle is repeated continuously until the thermostat registers that the set temperature has been reached. In refrigerators with No Frost another stage is added: defrosting. Every 8–12 hours of operation, the compressor stops, the heater turns on, which melts the ice on the evaporator, and the fan blows moisture out. That is why such models do not require manual defrosting.

Interesting fact: in refrigerators with Low Frost (for example, Bosh KAN58A55) the evaporator is coated with a special compound that reduces the formation of frost, but does not eliminate it completely. This is an intermediate option between the drip system and No Frost.

3. Diagram of the internal structure: where is everything

To better understand how a refrigerator works, consider a typical layout of parts using the example of a two-chamber model with an upper freezer (for example, Indesit DF 4180 W).

B freezer chamber (top compartment) are usually located:

• 🧊 Evaporator —a metal panel with tubes where ice forms (in drip models).
• 🌀 Fan —only in systems No Frost, distributes cold air.
• 🔥 Defrost heating element — heating element for removing frost (in No Frost).

In refrigerator compartment (lower compartment) you can find:

• 🌡️ Thermostat —temperature sensor, often hidden behind a plastic panel.
• 💧 Drainage hole — for water drainage during defrosting (in drip systems).
• 📡 Door closing sensor —in models with an alarm.

Rear of the refrigerator (under the back cover) hidden:

• ⚙️ Compressor —at the bottom, often black.
• 🔄 Condenser —a grid of tubes, can be open or closed.
• 🔌 Start relay —a small box nearby with a compressor.

In modern models (for example, Liebherr CNef 4815it can be additional fan for uniform distribution of cold in both chambers, and also electronic control unit with a display that replaces mechanical thermostat.

Where is the filter drier?

The filter drier is a small cylinder located on the tube between the condenser and the capillary tube. It removes moisture from the refrigerant and prevents the capillary from freezing. In most refrigerators, the filter is hidden under the back panel and looks like a small metal “tablet” with holes.

4. Materials and thermal insulation: why is it important

The quality of thermal insulation directly affects energy efficiency the refrigerator and its ability to maintain a stable temperature. Modern models use the following materials:

• 🏗️ Polyurethane foam (PPU) —the most common insulation. Fills the space between the inner and outer walls of the case.
• 🧱 Vacuum insulation - used in premium models (for example, Miele KFN 29233 D), where a vacuum is created between the walls for better thermal insulation.
• 🛡️ Fiberglass - rarely, mainly in old or budget models.

The thickness of the insulating layer is usually 4–6 cm. The larger it is, the better the refrigerator retains cold, but the larger its dimensions. For example, in compact models for offices (for example, Birusa 54) the insulation is thinner, so they are less economical.

The refrigerator body is made of:

• 🔲 Galvanized steel —cheap models.
• 🖌️ Plastic with metal coating —middle segment.
• 🛡️ Stainless steel —premium models (for example, Smeg FAB32).

Internal shelves and drawers are made of impact-resistant plastic or tempered glass. Glass shelves can withstand greater weight (up to 25–30 kg), but are more expensive. In some models (for example, Liebherr) they are based on silver ions, which inhibit the growth of microbes. antibacterial coatings based on silver ions, which inhibit the growth of microbes.

⚠️ Attention: If the rubber seal on the door has lost its elasticity, the refrigerator begins to consume 15-30% more electricity. Check its condition. at least once a year.

5. Frequent malfunctions and their connection with the internal structure

Knowledge of the internal structure of the refrigerator helps to quickly diagnose malfunctions. Let's consider the most common problems and their causes:

One of the most insidious malfunctions is refrigerant leakIt occurs due to microcracks in the tubes (often in solder areas) and leads to the fact that the refrigerator stops freezing, although the compressor is running. The leak can be detected by the following signs:

• The compressor runs without stopping, but the temperature does not drop.
• The condenser remains cold (normally it should heat up).
• On oil stains are visible on the back wall (the refrigerant is mixed with oil).

If you suspect a leak, do not try to refill the refrigerator yourself this is dangerous and requires special equipment. Contact a service center.

6. How to check the functionality of key components

Some elements of the refrigerator can be diagnosed independently without disassembling the case. components:

Checking the compressor

1. Unplug the refrigerator.
2. Remove the back cover (if it is removable).
3. Find the compressor - it is a black “barrel” with tubes.
4. Turn on the refrigerator and listen: if the compressor does not hum, check the start relay (small box next to it).
5. If the relay clicks, but the compressor does not start, the winding may have burned out.

Checking the thermostat

1. Turn off the refrigerator.
2. Remove the thermostat knob (usually it is attached to a latch).
3. Under it you will see a plastic box with wires - this is the thermostat.
4. Ring the contacts with a tester: at room temperature they should be are closed.

Checking the condenser

• Clean the condenser from dust with a vacuum cleaner or brush.
• Turn on the refrigerator and after 15 minutes check the temperature of the tubes: they should be warm.
• If the condenser is cold, a leak is possible refrigerant or clogged capillary tube.

If you are not confident in your abilities, it is better not to risk it. For example, replacement of refrigerant requires. evacuation of the system and special skills. Incorrect actions can lead to complete failure of the refrigerator.

7. Modern technologies: what has changed in refrigerators in 2026

Manufacturers are constantly improving the internal structure of refrigerators to make they are more economical, quieter and more functional. In 2026, among the key trends:

• ⚡ Inverter compressors - are now installed even in budget models (for example, Atlant XM 4625-101They consume 30-40% less electricity and operate almost silently.
• 🤖 Artificial intelligence —premium refrigerators (for example, Samsung Family Hub+) use sensors that analyze the user's habits and adjust the temperature to the rhythm of life.
• 🌿 Antibacterial coatings —no longer only on shelves, but also in the air duct system (for example, in models Panasonic NR-BN30A1).
• 🔋 Rechargeable systems — some models (for example, EcoFlow Glacier) can be powered by portable batteries, which is important for cottages and country houses.

Another innovation is modular refrigerators, where the user can independently change the location of the cameras (for example, Liebherr MonolithThis is convenient for small kitchens where you need to optimize space.

In systems No Frost now use brushless fanswhich last longer and are quieter. And in some models (for example, Haier A3FE742CGMJa function has appeared that freezes food 2 times faster due to increased circulation air. "Super freezing", which freezes food 2 times faster due to increased air circulation.

⚠️ Attention: In refrigerators with the function Smart Diagnosis (for example, LG GC-B247JLVL) you can carry out preliminary diagnostics faults using a mobile application. However, the final verdict must be given by the master - automatic systems sometimes make mistakes.

8. Operating tips: how to extend the life of a refrigerator

Even the most reliable refrigerator will last longer if you follow simple operating rules. This is what service center engineers recommend:

• 🧹 Regular cleaning — once every 3-6 months, wash the internal surfaces with a warm soda solution (2 tablespoons per 1 liter of water). Avoid abrasive products!
• 🔌 Stable voltage —connect the refrigerator via stabilizerif your network has frequent surges. This will protect the compressor from overheating.
• 🚪 Correct opening of the door —do not keep it open for more than 30 seconds. Every extra hour of operation in this mode shortens the life of the compressor by 5–7 days.
• 🍖 Placement of products —do not put hot foods in the refrigerator, let them cool to room temperature. Do not jam the shelves to capacity - this interferes with air circulation.
• ❄️ Defrosting - even if you No Frost, once a year turn off the refrigerator for 12-24 hours for prevention. This helps remove ice that may form in hidden places.

Pay special attention sealing rubber band. Over time, it loses its elasticity, and the refrigerator begins to “suck” warm air. Check its condition with a simple test: close the door by placing a sheet of paper between it and the body. If the sheet falls out, it’s time to change the rubber band.

If the refrigerator is in a room with high humidity (for example, in a kitchen with poor ventilation), condensation may accumulate on the condenser, which leads to corrosion. The solution is to use moisture absorbers (for example, silica gel bags) or install an additional fan.

FAQ: Frequently asked questions about the internal structure of the refrigerator

Why is the refrigerator humming but not freezing?

This is a typical symptom compressor malfunction or refrigerant leaks. Other possible reasons:

• Clogged capillary tube (refrigerant does not circulate).
• Failure of the start relay (compressor does not starts).
• Thermostat malfunction (the compressor works, but does not turn off).

For diagnostics, turn off the refrigerator, let it stand for 1-2 hours, then turn it on again. If there is a hum, but there is no cooling, call a technician.

Is it possible to fill the refrigerator with freon yourself?

No, it is a dangerous procedurewhich requires:

• Special equipment (vacuum pump, pressure gauges).
• Knowledge about the types of refrigerants (for example, R600a explosive!).
• Ability to solder copper-aluminum tubes.

Incorrect charging can lead to to explosion (if you overdo it with freon) or compressor breakdown.

What is the difference between No Frost and Low Frost?

No Frost - a fully automatic system where ice is removed using a heater and a fan. Low Frost —a hybrid system where frost forms more slowly due to a special coating of the evaporator, but is not completely eliminated. Main differences:

Parameter	No Frost	Low Frost
Defrosting	Not required	Required once every 1-2 years
Humidity	Low (products may dry out)	Higher, closer to the drip system
Noise	Higher (due to the fan)	Lower

Why does condensation form on the back wall of the refrigerator?

This normal for models with drip system —moisture from the air condenses on the cold wall and flows into the drainage hole. However, if there is too much condensation or it appears in models with No Frost, the following reasons are possible:

• High humidity in the room (for example, after cooking).
• Clogged drainage hole (water does not drain, accumulates on day).
• Thermostat malfunction (the refrigerator operates in high mode).

Solution: check the drainage hole (clean it with a cotton swab) and make sure that the door closes tightly.

How much does it cost to repair a refrigerator compressor?

The cost depends on the model and type of compressor:

• Replacement of a linear compressor — from 5,000 to 12,000 rubles (including work and refilling with freon).
• Replacement of an inverter compressor — from 8,000 to 20,000 rubles (they are more expensive and require precise adjustment).
• Winding repair - from 3,000 to 6,000 rubles (if the compressor has not burned out completely).

In some cases (for example, in refrigerators older than 10 years) it is cheaper to buy a new one than to repair an old one.