For many hundreds of years, people cut and stored large blocks of ice to keep food cool, ice chests! However, refrigeration technology came into existence in the 18th century, and the first domestic refrigerators (fridges) appeared on the commercial market in 1913.
Today, fridges are required for many different reasons. From medical cold storage, to refrigerated transport vehicles, and of course, the household refrigerator. Despite changes in style and design, the basic materials used in refrigerator manufacturing have remained relatively the same.
Frame and Housing – Steel (made using fossil fuels)
Refrigerators consist of around 60 percent metal, the bulk of the weight due to the steel frame and components. The average refrigerator contains around 55 kg of steel, according to estimates of the Appliance Recycling Information Institute. This steel gives the fridge frame its strength and durability, allowing it to last for many years and helping your refrigerator magnets take hold on its surface. Modern units may be coated with a thin skin of aluminium or stainless steel, though some are simply solid steel covered with a layer of paint, laminate or other coating.
Interior Plastic (made from fossil fuels)
About 40 percent of a refrigerator is plastic materials. The average fridge is made up of about 9 kg of plastic. Moulded polyurethane and polystyrene form the interior panels and liners, as well as plastic shelves and supports in some units. While older models may contain glass, the clear door and drawer fronts in modern fridges are generally crafted from polystyrene, polycarbonate or acrylic (courtesy of fossil fuels). Some fridges contain aluminium shelves and brackets, others rely on plastic-coated wire racks.
Effective insulation in the walls of a refrigerator keeps cold in and heat out, maximizing energy efficiency and keeping operating costs low. Modern fridges use thin sheets of polyurethane foam, which are layered between the interior plastic liner and the outer skin of the unit. The introduction of polyurethane foam has made modern fridges 60 percent more efficient than those manufactured just 15 years ago.
Though the average refrigerator contains just around .25kg of refrigerant gas. This material plays an important role in the operation of the unit. The earliest refrigerants contained lethal chemicals like ammonia and methyl chloride, which led to some deaths when they leaked. By the 1920s, manufacturers had turned to safer CFCs, such as Freon. As scientists learned more about the environmental impact of CFCs, refrigerator makers switched to HCFCs and other safer refrigerants.
While the compressor, condenser, evaporator and other working components make up just a small portion of the materials used in the fridge, they are vital to the fridge’s operation. The fins and tubing in a refrigerator are generally crafted from aluminium, copper or metal alloys that offer a high degree of thermal conductivity. Casing used around the motor often consists of steel, though manufacturers may also use aluminium or other alloys. Fan blades within the evaporator can be made of plastic, aluminium or steel depending on the model.
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