Exploring refrigerator materials: What’s Your refrigerator made of?

Have you ever wondered what the appliance where you store your food is made of? Yes, I’m talking about your refrigerator. Just as a city has different neighborhoods and streets, a refrigerator is also made of different materials.

In this article we will break it down part by part so that you can better understand how this appliance that is so important in our homes works.

The exterior of the refrigerator

The first glance at a refrigerator reveals a solid, durable exterior. Most modern refrigerators are made of stainless steel, which is not only corrosion resistant, but also gives your kitchen a sleek look. This material is not only attractive but also easy to clean, which is essential for maintaining a tidy kitchen.

Traditionally they were made of painted galvanized steel. However, more modern models, excluding those made of steel, use plastics such as ABS or polycarbonate, which are lighter and more resistant to corrosion.

Doors

Refrigerator and freezer doors are made from rigid plastics like ABS or polycarbonate, sometimes with a steel layer for added strength.

They feature magnetic gaskets for an airtight seal and metal hinges. Some include tempered glass for interior visibility.

Seals

Door seals are strips of flexible PVC or silicone. To prevent cold air leaks, rubber or plastic seals are used at various points. There are also adhesive gaskets that seal the external cabinet.

Cooling System

Refrigerants

These enable cooling by absorbing and releasing heat in a closed cycle. Commonly used are CFCs (chlorofluorocarbons) like Freon R-134a, and HCFCs (hydrochlorofluorocarbons) like R-141b, though they are being phased out due to ozone layer damage. Eco-friendlier alternatives are HFCs (hydrofluorocarbons) like R-600a, and natural gases like propane or isobutane.

Pipes

Pipes transport refrigerant in liquid and vapor forms between components. Made of copper for its high thermal conductivity, with protective coatings of plastic or tin. Some use stainless steel. In more economical models, these can be made of aluminum.

Compressor

The compressor is made from aluminum and steel alloys. It pumps and compresses gaseous refrigerant to start the cooling cycle. Depending on the model, they may house an electrically driven reciprocating compressor. The more powerful ones use a rotary compressor mostly.

Evaporator

The evaporator contains copper or aluminum tubes carrying the refrigerant, with aluminum fins soldered on to maximize heat transfer. All enclosed in a metal housing, usually steel. The tubes have inlet and outlet connections for refrigerant circulation. Some models include a corrosion-resistant coating on the copper tubes. In summary, the essential components of the evaporator are the conductive tubes, heat transfer fins, support housing, and connections for refrigerant flow.

Condenser

Composed of copper coils with aluminum fins to dissipate heat into the external environment. It liquefies the hot compressed refrigerant from the compressor.

Inside the Refrigerator

Insulation

Crucial for maintaining cold temperatures. Rigid polyurethane foam is injected between interior and exterior walls. Other insulation materials include extruded polystyrene and fiberglass.

Fans

Made with durable plastic materials, mainly polymers like ABS or polycarbonate. These technical plastics provide robustness to withstand low temperatures.

They feature rigid plastic blades or propellers, driven by an electric motor to generate air movement. The blades are aerodynamically designed to maximize airflow.

Filters

Modern fridge filters are designed with highly effective materials for odor and particle absorption.

Polyurethane foam is a key component, its porous structure capturing bacteria and contaminants in the air. Synthetic fibers also have microscopic pores that effectively retain airborne particles.

The star material is granulated activated carbon, whose extreme porosity gives it a huge capacity to absorb odor-causing gases. Combining these materials achieves complete filtration.

Thermostat

The thermostat is an essential component that maintains optimal temperature inside the fridge. Made with heat-sensitive materials like resistors and semiconductors, they accurately detect temperature changes.

Common types include:

  • NTC Thermistors: Ceramic resistors whose electrical resistivity changes with temperature. As interior temperature drops, their resistance increases, activating the compressor.
  • Bimetallic Sensors: Strips of two metals bonded together that twist and move a switch due to temperature changes. Used in mechanical thermostats.
  • Integrated Control Circuit: Processes sensor signals and controls the compressor and fan according to the set temperature.

Interior Light

Ever wondered how your fridge is lit? Here are more details about its components:

  • LED bulbs are made from light-emitting diodes, encapsulated in durable plastic or ceramic materials. They offer efficient, long-lasting brightness with low power consumption.
  • LED strips consist of multiple miniature LEDs soldered onto a flexible printed circuit. Covered with a polycarbonate or silicone sheet for insulation and light diffusion.
  • The optical compartment distributing the lighting is molded from translucent polycarbonate or acrylic, materials that maximize light transmission and diffusion.
  • LEDs are chosen in cool shades, between 6000-6500K, for daylight-like illumination that doesn’t alter the appearance of food.

Shelves and Drawers

Shelves are typically made of plastic or tempered glass, highly resistant to bear weight without issues. Metal grills are also great for placing bottles and allowing cold air circulation.

And the drawers are made of special plastic for food preservation. There are ones for fruits and vegetables, which maintain ideal humidity. Others are for meats and fish, designed to prevent odor and bacteria mixing.

Conclusion

As we have seen, refrigerators and freezers combine a variety of materials carefully chosen for optimal efficiency and durability.

The external cabinet protects the delicate cooling system composed of copper pipes, a compressor, evaporator, and condenser, all sealed and insulated to maintain low temperatures. Next time you open your refrigerator, you’ll know everything inside it besides the food!

Frequently Asked Questions

What are most modern refrigerator exteriors made of?

Modern refrigerator exteriors are usually made of plastics like ABS or polycarbonate, instead of the painted steel used previously.

What materials are used to seal the doors?

The doors are sealed with strips of flexible PVC or silicone. There are also adhesive gaskets to seal the entire cabinet.

What refrigerants are more environmentally friendly?

HFC refrigerants like R-600a and natural gases like propane and isobutane are better for the environment as they do not harm the ozone layer.

What are the internal pipes primarily made of?

The pipes are usually made of copper due to its high conductivity, with plastic or tin protections. Some use stainless steel.

What type of compressor is most common in domestic refrigerators?

The electrically driven reciprocating compressor is most common in domestic refrigerators, while the more powerful ones have a rotary compressor.

What materials are refrigerators mainly made of?

Modern refrigerators are primarily made of Stainless Steel on the exterior and interior. Aluminum or Copper in evaporators, condensers, and refrigerant wiring. Insulating foams between their external and internal casings, Tempered Glass and Plastic Polymers for trays and shelves.

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