Students seeking refrigeration and HVAC certification might be interested to learn more about refrigeration's long and colorful history. No longer exclusive to the wealthy, in-home refrigerators have come a long way since their invention. Cooling units come in many sizes, too - and have a wide variety of uses.

In 1911, the wealthiest Americans began using individual, stand-alone refrigerators in their homes. Home units were a great new convenience at that time - before, people had to salt foods, immerse them in brine; or deep freeze them in ice-houses or underground, in order to avoid food-borne illnesses cased by spoiling and contamination.

As refrigeration technologies developed, refrigerators - and later, combined refrigeration-freezer units - became available to middle-class homeowners. General Electric was a major innovator of home refrigeration units, and the Kelvinator and Frigidaire were popular models, later, as well.

Today, fewer than 0.5 percent of Americans are lacking refrigerators in their homes. Refrigeration is a wonderful asset to food preservation and food-borne illness prevention. It allows people to keep foods like fresh vegetables, meat, and ice cream in their homes, and to safely eat them long after they've bought them.

Before the 1980s, a major cooling component in refrigeration was the chemical Freon. Freon is a chlorofluorocarbon that acts as a refrigerant. Freon is considered to be safe for in-home use, and Freon enabled home refrigerators to be mass-manufactured for home use.

The major decades of home refrigeration boom were the 1950s and 1960s. During these decades, refrigerators were widely advertised, and became affordable appliances for most Americans. Many refrigeration units came with extra, time-saving features such as automatic defrost, which made these units even more convenient.

In the 1970s and 1980s, environmental issues became a major concern, not just for politicians, but for average Americans, as well. Chlorofluorocarbons became recognized as prime contributors to ozone layer depletion. By late 1995, Freon was banned from being imported to the United States, and the chemical can no longer be produced in this country.

Of course, these environmental regulations have created new jobs for HVAC professionals. Trained refrigeration and cooling technicians are needed to replace equipment currently using Freon as a cooling agent to bring refrigeration units in line with environmental laws.

Refrigeration isn't just used in homes and apartments, though. Across America, there are vast refrigerated warehouses that store perishables such as produce and meats, prior to shipping. Large trucks have refrigerated interiors, allowing perishable food items to be shipped across long distances.

There are also many industrial uses for refrigeration technologies. Gases such as oxygen must be deeply refrigerated below their boiling points in order to become liquefied. Refrigeration is also useful for dehumidifying air; the process of refrigeration causes water vapor to condense. Certain steps in manufacturing processes require that materials be processed at low temperatures, so commercial refrigeration is highly useful in factories and plants. Refrigeration is also used during blacksmithing and steel manufacturing as part of the process of hardening metals.

Hockey and skating rinks, offices, and convention centers use refrigeration, too. Refrigerants are used to keep the ice on a rink hard, and to maintain correct temperatures for skating. Large industrial refrigerators, personal mini-fridges, soda machines, and coolers are used in offices and meeting centers, large and small.

What do all of the uses of refrigeration have in common? They require skilled technicians to maintain and repair the cooling units, of course! When completing HVAC and refrigeration certification, students are trained to enter a wide variety of interesting careers in the cooling and refrigeration fields.