For thousands of years, people cut and stored large blocks of ice to keep food cool. Refrigeration technology came into existence in the 18th century, and the first domestic refrigerator hit the market in 1913. Today, fridges are in more than 99.5 percent of U.S. households, according to the Association of Home Appliance Manufacturers. Despite changes in style and design, the basic materials used in refrigerator manufacturing have changed relatively little.
Frame and Housing
Refrigerators consist of around 60 percent metal, the bulk of the weight coming from iron and steel. In fact, the average refrigerator contains 123 pounds of steel, according to estimates of the Appliance Recycling Information Institute. This steel gives the frame of the fridge 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 aluminum or stainless steel, though some are simply solid steel covered with a layer of paint, laminate or other coating.
About 40 percent of a refrigerator is plastic materials. The average fridge is made up of about 20 pounds of plastic, according to Baltimore Gas and Electric. Molded 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. Some fridges contain aluminum 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 at bay. 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, according to the European Diisocyanate and Polyol Producers Association .
Though the average refrigerator contains just half a pound of refrigerant gas, according to BGE, 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 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. A 2014 study at the University of Virginia revealed the potential for eliminating refrigerants entirely and cooling refrigerators using magnets in the future.
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 aluminum, 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 aluminum or other alloys. Fan blades within the evaporator can be made of plastic, aluminum or steel depending on the model.